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CFISD First Grade MathStrategies for Addition and Subtraction within 20

(Introduce Missing Part & Using Doubles)Teacher Notes Page #

Unit Title Doubles + 1

Doubles + 2

Addition with ten frames

Adding 3 numbers

Introducing Missing Part

More Missing Part

Doubles for Subtraction

Using a Number Line for Subtraction

3

5

7

9

11

16

21

23TEKS The student is expected to:

1.3A use concrete and pictorial models to determine the sum of a multiple of 10 and a one-digit number in problems up to 991.3B use objects and pictorial models to solve word problems involving joining, separating, and comparing sets within 20 and unknowns as any one of the terms in the problem such as 2 + 4= ?; 3 + ? = 7; and 5= ?+51.3C compose 10 with 2 or more addends with and without concrete objects1.3D apply basic fact strategies to add and subtract within 20, including making 10 and decomposing a number leading to a 101.3E explain strategies used to solve addition and subtraction problems up to 20 using spoken words, objects, pictorial models, and number sentences1.3F generate and solve problem situations when given a number sentence involving addition or subtraction of numbers within 201.5F determine the unknown whole number in an addition or subtraction equation when the unknown may be any of the three or four terms in the equation1.5G apply properties of operations to add and subtract two or three numbers

Vocabulary Addition, Subtraction, Joining, Separating, Comparing, Equal, Sum, Difference, Doubles

Tips for Essential Understandings are included for professional CFISD TN 15-16 Addition and Subtraction within 20 1

http://images.google.com/imgres?q=clip+art+for+subtraction&start=265&hl=en&biw=1024&bih=587&tbm=isch&tbnid=AwmDG8Uz0CKUAM:&imgrefurl=http://www.canstockphoto.com/illustration/subtraction.html&docid=Si6yKMUvNScJDM&imgurl=http://ec.l.thumbs.canstockphoto.com/canstock6867801.jpg&w=150&h=35&ei=xTGRUNn0I4n02wX-54GgDQ&zoom=1&iact=hc&vpx=286&vpy=382&dur=1969&hovh=33&hovw=144&tx=125&ty=25&sig=110454929349858035179&page=13&tbnh=33&tbnw=144&ndsp=22&ved=1t:429,r:7,s:265,i:238

Teachers development purposes. To improve as math educators we must have a deep understanding of foundational math concepts.Essential Understandings: Addition and its inversely related operation, subtraction, are powerful foundational concepts in mathematics, with applications to many problems situations and connections to many other topics.Addition determines the whole in terms of the parts, and subtraction determines the missing part.

Fact Fluency

Please practice these activities that support the CFISD Fact Fluency Plan. All of the following activities can be found in the book Mastering the Basic Math Facts in Addition and Subtraction by O’Connell and Sangiovanni.Hop the Line (p. 44)Domino Addition (p. 59)Ten More (p. 71)Fill the Chart (p. 72)

CFISD TN 15-16 Addition and Subtraction within 20 2

First Grade Teacher NotesStrategies for Addition and Subtraction within 20

Doubles +1

TEKS:1.3D apply basic fact strategies to add and subtract within 201.3E explain strategies used to solve addition and subtraction problems up to 20 using spoken words, objects, pictorial models, and number sentences

Materials:Anchor chart doubles (Resource)Doubles fact cards (Resource)Unifix cubesThree in a Row (Resource)Doubles and Doubles +1 Practice Sheet (Resource)

Instruction:Mathematicians, help me solve this problem:Sara has 3 cookies. How many more cookies does she need to have 5?Turn and tell your partner your thinking. You are doing a better job each day justifying your answers. I am proud of your mathematical thinking!

We have been learning the strategy of doubling a number to add two numbers which are the same. If we memorize our doubles, we will not have to count on our fingers or count manipulatives. We will know those facts quickly. I’m going to show you another way to use your doubles facts for more addition problems.

Travis has 4 Xbox games. He wants to save money for 5 more. How many games will he have in his collection? You may know this answer because you know your facts to 10. You also know how to add 4 + 5 on the ten frame. You also know how to count 4 + 5 more on your fingers and other strategies. But this time use your doubles facts first. Which doubles facts would be helpful? (Wait for possible suggestions.)4 + 4, right? OK, so 4 + 4=8 but he wants 5 more. So, if I know 4 + 4=8 then I would just count one more than 4 to get to 5. So I would say in my mind 8, 9. There will be 9 games in his collection. Using our doubles facts plus 1 more is another helpful strategy. We call it doubles +1.

Let’s try another:Carol has 7 thank you notes. Her mother gives her 8 more to sign. How many thank you notes does she have altogether? Let’s think together about how doubles may help us solve this problem quickly.


(Wait for any possible suggestions from your students.) I am thinking that I could possibly consider the numbers 7 + 7. If I know the doubles fact 7 + 7=14, I could add 1 more and that would be 15. I just count 14, 15. I don’t have to start back at 1 and count all the way from 1 to 7 and then 8 more. That is much faster! Let’s try another.

Bingo has 8 bones on Monday. On Tuesday he digs up 9 more. How many bones does Bingo have now?Use your doubles facts first. Turn and tell your learning partner which doubles facts you are thinking will be the most helpful. (If students choose lower numbers such as 6 + 6, or 7+7, explain that they would want to choose one of the numbers in the problem. They may need this to be modeled with unifix cubes showing two sets; one with 8 and one with 9. Since you do not have 2 full groups of 9, you would choose the doubles fact for 8.) So we know 8+8=16 plus one more would be 17.Turn and tell your learning partner why doubles and doubles plus 1 help us add bigger numbers. Point out to your students that the doubles + 1 strategy is most efficient when the numbers are very close together. For example, to solve 2 + 9, doubling 2 would not be very helpful or efficient. Ask the students to think about that and justify the reason. We want to teach them many different foundational strategies this year that they will decide if and when to use in the future.

Group #1: (Partner) Three in a Row (Resource) Students will select a doubles fact card and cover answer with a chip or cube. The object is to get three in a row on chart.

Group #2 (Independent) Doubles and Doubles +1 practice sheet.

Group #3 (Teacher directed-Small group) Practice doubles and doubles plus one problems with your students. Practice using the doubles strategies for both addition and subtraction problems.



Doubles +2

TEKS:1.3D apply basic fact strategies to add and subtract within 201.3E explain strategies used to solve addition and subtraction problems up to 20 using spoken words, objects, pictorial models, and number sentences

Materials:Doubles Anchor chart (resource)Unifix cubesWhite boards/markersDoubles fact cards (resource)

Instruction:Ready for mathematical thinking?OK, try this:Maria has 7 games. She gets 3 more. How many games does she have?Turn and tell your partner what you are thinking. Is it helpful to know the number bonds for ten? Did you use that strategy or did you use another like counting on?Now think about this:Maria has 10 games. She gives 3 of them to her friends. How many games does Maria have now?Turn and tell your partner how you can use the addition sentence 7 + 3 = 10 from the first problem to help solve the second problem. Why does that work?

What are doubles facts? (Addition facts with the same addends) Why is 3 + 3 a doubles fact? (The addends are the same) What doubles facts do you know? Let’s review our Anchor chart for Doubles.

Today I want to show you another way doubles will help you add bigger numbers. And of course, if they help with addition, knowing doubles facts will help with subtraction.I have 7 unifix cubes here. I have another group of 9 unifix cubes. If I want to know the total amount of unifix cubes I could count them one-by-one. Let me do that and you can time me. Have a student hold a timer and count the seconds or set a timer on your computer that projects to the whole class. Count aloud as you stack each unifix cube; 1,2,3,4,5,6,7, (Exaggerate your counting to stress the point that counting by ones takes longer and is not efficient.) 8, 9, 10,11,12,13,14,15,16. OK stop the timer. How long did that take?Record time on board.CFISD TN 15-16 Addition and Subtraction within 20 5

Now let me use the doubles strategy for addition.7 + 9 =?7 + 7 =14 plus 2 more equals 16.OK stop the timer. Record the time.Which was quicker? Wow! I love Math! I love knowing different strategies so that I am even quicker and really thinking about numbers and how they work!Did you notice that I couldn’t just use the doubles + 1 strategy that we talked about yesterday? I had 9 which is 2 more than 7 so I had to add my doubles plus 2.That is what we will practice today.

Ann built two towers. One tower has 4 cubes. The other tower has 6 cubes. How many cubes did Ann use?Use your doubles facts to begin. Now how many more do you need to add by counting on? Have students make the two towers with unifix cubes. Have them show two equal towers of 4. Then have them add the last two cubes to the tower.Have them write the number sentence on the table or white board.4 + 6 =10.Have them write the strategy they used to solve.I added double 4 and then counted on +2.

Jim built two towers. One tower has 7 cubes. The other tower has 9 cubes. How many cubes did Jim use?Use your doubles facts to solve the problem. Write a sentence explaining which strategy you used.

Suzie built two towers. One tower had 6 cubes. The other tower had 8 cubes. How many cubes did Jim use?Use your doubles facts to solve the problem. Write a sentence explaining which strategy you used.

Group #1: (Partner) Adding with Playing cards (Jacks, Queens and Kings=10)

Group #2 (Independent) Addition and Subtraction Practice Problems

Group #3 (Teacher directed-Small group) Practice adding doubles +1 and doubles +2.



Addition with ten frames

TEKS:1.3A use concrete and pictorial models to determine the sum of a multiple of 10 and a one-digit number in problems up to 99

Materials:Red and blue unifix cubes.10 Ten frames (magnetic or drawn on chart or board)Addition with Multiples of 10 Practice Sheet (Resource)

Instruction:Today’s thinking problem is:Mr. Teacher has two teams in his class. He asked Team A to solve 7 + 2. He asked Team B to solve 2 + 7. What answers did the two teams get? Why? Turn and tell your partner what you are thinking.Ask one student to show the class 2 + 7 with red and blue unifix cubes. Ask another student to show the class 7+2 with the same blue and red unifix cubes. Why are both sets equal to 9?They do not need to know that this is the commutative property, but understanding of the property will be developing.

Mathematicians, you are learning and using many strategies to add and subtract.Today we will revisit our ten frames to add bigger numbers.Show a ten frame on the board. Have students tell you how many are represented if all the spaces in the ten frame are filled. Add dots to the second ten frame and choose different students to count the dots for the class. Focus on the numbers from 15-19 using the number sentences:10+5=15.10+6=16.10+7=17.10+8=18.10+9=19.

Show additional ten frames and have students count by tens to 90.Model the adding of multiples of ten plus a one-digit number. For example, 3 full ten frames equals 30, plus 2 dots in the fourth ten frame equals 32. If your teacher is 30 years old, in 2 more years he will be?If your teacher is 70 years old, in 6 more years she will be?7 full ten frames plus 6 dots in the eighth ten frame equals 76.Model 29, 45, 91, and 87 writing the number sentences on the board such as 20 + 9=? 40+5=? 90 +1=? 80+7=?CFISD TN 15-16 Addition and Subtraction within 20 7

Model number sentences written like this as well:20+4

Encourage students to use their subitizing skills to add these numbers, not one-by-one counting as much as possible. If you have a multiple of ten such as 10, 20, 30, 40, 50, 60, 70, 80, or 90 plus another number you can use this strategy and add the numbers quickly in your head without a ten frame!

Group #1: (Partner) Three in a Row (Resource) same as yesterday

Group #2 (Independent) Addition with multiples of 10 Practice Sheet (Resource)

Group #3 (Teacher directed-Small group) Practice adding with multiples of 10. Have students make groups of ten (tens) with unifix cubes and single cubes. For example, 60 + 8-make 6 groups of ten and 8 singles. Have them count to ensure understanding of strategy. Record observations in monitoring notebook.



Adding 3 numbers

TEKS:1.3C compose 10 with 2 or more addends with and without concrete objects1.5G apply properties of operations to add and subtract two or three numbers

Materials:3 different colors of unifix cubesAddition with 3 Numbers Practice Sheet (resource)

Instruction:Think about this: Mrs. Teacher has 2 students in her guided reading group. She asks 1 more to join the group. Then she asks 1 more student to join them. How many students are in the group now? Think about that…now turn and tell your learning partner what you are thinking.Did you realize you can add 3 numbers together? Sometimes you might have to add 6 numbers together!! Wow! Mrs. Principal might want to add all the students in the whole school!! She would need to add each group of students from each classroom. We have 60 classrooms here at our school so she would be adding 60 groups of numbers together. Amazing!! Our Principal needs to be very smart and a good math thinker!Today we are just going to practice adding 3 numbers together.Kelly sees 7 red birds. Bill sees 3 blue birds. Joe sees 1 yellow bird. How many birds do they see?How many parts are in this story? (3) What is the addition sentence? 7 + 3 + 1 =?Model solving this problem using red, blue, and yellow unifix cubes. Discuss different ways to add 3 addends. They may realize that 7 + 3 = 10 and add those two numbers first. They may need to count by ones adding the three groups as they count.Help students connect the train to show that the sum does not change even if we count the three groups in different order.(7 + 3) + 1 = 11 and 7 + (3 +1) = 11.

Essential Understandings:The Associative Property for addition allows us to regroup addends; it is generally stated formally as follows:a + (b + c) = (a +b) + cBeing able to use the associative property fluently is important in developing good number sense.


Breanna collected 4 red marbles. She buys 4 purple marbles and 2 blue marbles.How many marbles does Breanna have?Show me how to solve this problem using 3 different colors of unifix cubes. Which two sets will you add together first? Does knowing the doubles fact for 4 help you here?Or did you solve the problem another way?

Group #1: (Partner) Doubles fact cards- practice with your partner

Group #2 (Independent) Addition and Subtraction practice problems

Group #3 (Teacher directed-Small group) Practice adding with 3 numbers. Encourage the use of different strategies to be most effective problem solvers.



Introducing Missing Part

TEKS:1.3B use objects and pictorial models to solve word problems involving joining, separating, and comparing sets within 20 and unknowns as any one of the terms in the problem such as 2 + 4= ?; 3 + ? = 7; and 5=? +51.3E explain strategies used to solve addition and subtraction problems up to 20 using spoken words, objects, pictorial models, and number sentences1.5F determine the unknown whole number in an addition or subtraction equation when the unknown may be any of the three or four terms in the equation

Materials:2-color countersStudent copies of the story problems

Instruction: Mathematicians, help me solve this problem:Superman rescued 18 people from danger. If he rescued 9 children, how many adults did he rescue? Take a minute to think about your answer. Just use all you know about numbers and mathematics, do not use a pencil, just your brain.Now turn and tell your learning partner what your answer is. You will need to justify your answer; that means to explain what you were thinking about to solve the problem. If your learning partner has a different answer, that is OK. Maybe if you are able to explain and justify your thinking, she will agree with you and learn from your thinking.Remind your students to always consider the doubles strategy for quick addition and subtraction problems.

You are all such great thinkers. We are going to start a new topic in Math today. We are going to focus on addition and subtraction-but I will introduce another situation that also makes us think about what is missing.

Boys and Girls, I want to tell you a story.John put 11 two-color counters on the table. Eight of them show the red side. How many of the counters show the yellow side?Let’s use our two-color counters and the 4-step problem solving process to show our thinking.


Reread the question. What are the most important words in the question? (Counters, yellow)WHO is the problem about? WHAT is the problem about? Begin the model drawing.

C yellow J

Instruct the students to turn the 11 counters all to the yellow side. Draw the model.How many boxes will we draw? Why?Where will we draw them?Label the total amount above the model.

C yellow


How

Strategy

Details

Main Idea

How

Strategy

Details

Main Idea

J. C 11

The second sentence tells us that there are 8 red counters. So let’s turn 8 of these yellow counters on to their red side. Label your drawing with the letter R for the 8 red counters.

C yellow

Read the next sentence. Look at the model drawing. Is there anything we need to do to the model? (Yes, label yellow and place the?) Where will the question mark be written on the drawing? If you look at the drawing, the yellow counter amount is missing. This type of model drawing is called a “missing part.”

C yellow


How

Strategy

Details

Main Idea

J. C 11R R R R R R R R8

How

Strategy

Details

Main Idea

J. C 11R R R R R R R R

8

Y Y Y

?

Continue the 4-step process. Let’s complete the strategy box.What number sentence could be written to find the number of yellow counters? (11 – 8 =?)How could you find the number? (Count up) What number is the “missing part?” (3)

C yellow

11 – 8 = □ 11 – 8 = 3

Next, complete step 4.How did we find the answer? What vocabulary words could you use to describe what you did? Are there other ways to describe how you found the answer? (Subtract 8 from 11, found the difference between 11 and 8, counted up 3)

C yellow

11 – 8 = □ 11 – 8 = 3


How

Strategy

Details

Main Idea


8

Y Y Y

?

11 - 8 3

How

Strategy

Details

Main Idea


8

Y Y Y

?

11 - 8 3

Subtract 8 from 11.

When we looked at the model, a part was missing. Because we can subtract 8 from 11, this kind of subtraction is called “missing part.” I was thinking about that Superman problem again that we did in our heads at the beginning of this lesson. Was that a missing part problem? Turn and Tell your partner what you think.

Group #1: (Partner) Roll and Double It- Provide students with 20 counters. Roll a 1-6 die or 1-10 number die and make a row with that number of counters. Ask your partner to double it by making a row of the same size. Without counting, tell your partner how many counters there are in total. Count the total amount of counters.

Group #2 (Independent) Practice Problems-Addition review

Group #3 (Teacher directed-Small group) Walk the students through another 4-step problem involving missing part.Camila had 14 counters. 5 were yellow. How many were red?



More Missing Part

TEKS:1.3B use objects and pictorial models to solve word problems involving joining, separating, and comparing sets within 20 and unknowns as any one of the terms in the problem such as 2 + 4= ?; 3 + ? = 7; and 5=? +51.3E explain strategies used to solve addition and subtraction problems up to 20 using spoken words, objects, pictorial models, and number sentences1.5F determine the unknown whole number in an addition or subtraction equation when the unknown may be any of the three or four terms in the equation

Materials White boards, markers Unifix cubesStudent copies of the story problems

InstructionMathematicians, take out your white boards and put on your thinking caps. I want you to draw a shape with 4 vertices and 4 sides. Go!Now show your shape to your learning partner. Did you draw the same shape? Are you both correct? Justify your thinking.

Let’s look at another problem today together. While we read, think about whether this is an addition problem or a subtraction problem.

Mary has 12 friends. Seven of her friends are girls. How many friends are boys?

Read the story. What is the question? What are the most important words in the question? (Friends, boys) Let’s read for the details. WHO is the problem about? WHAT is the problem about? Draw the model.

HM boys M friends


How

Strategy

Details

Main Idea

Act out the FIRST sentence using the unifix cubes. How many unifix cubes will we use? Where should we put the unifix cubes? Draw the model.How many boxes will we draw? Why? Where will we draw them? What do we need to do next to our model? (Label) What will our label be? (12) Where will we put the label?

HM boys

Read the next sentence.Act out the SECOND sentence using the unifix cubes. You may want to replace the number of girl unifix cubes with a different color. Look at the unifix cubes. What does the second sentence tell us to do? How many unifix cubes? (7) What color do we want to use to show the girls? What do we need to do? Next, look at the model drawing. What do we need to do to the drawing? How many units do we use? (7)

HM boys


Details

How

Strategy

Details

Main Idea

M friends 12

How

Strategy Main Idea

M friends 12G GGGGG GB 7

Read the next sentence. Look at the unifix cubes. Is there anything we need to do to act out the sentence? What are we trying to find? (Look to the main idea.) Look at the model drawing. Is there anything we need to do to the model? (Yes, place the?)Where will the question mark go on the drawing? If you look at the drawing, the part that is missing is boys. This type of model drawing is called a “missing part.”

HM boys

Continue the 4- step process. Look at the strategy. What number sentence could be written to find the number of boys? (12 – 7 = □) How could you find the number? (Count up)What number is the “missing part?” (5)

HM boys

12 – 7 = □


How

How

Strategy

Details

Main Idea

M friends 12G GGGGG G

7 ?

How

Strategy

Details

Main Idea


7 ? 12 - 7 5

You may want students to label the cubes with B’s.

You may want students to label the cubes with B’s.

Next, complete step 4.How did we find the answer? What vocabulary words could you use to describe what you did? Are there other ways to describe how you found the answer?

HM boys

12 – 7 = □

When we looked at the model, a part was missing. Because we can subtract 7 from 12 this kind of subtraction is called

“missing part.”

Group #1: (Partner) Telling time practice with Judy Clocks- students will tell a time to the hour or half hour and partner will show the time on the practice clock.

Group #2 (Independent) Missing Part Practice problems using the 4-step process.

Group #3 (Teacher directed-Small group) Guide students step-by-step through the 4 steps to solve 1 or 2 subtraction problems.


How

Strategy

Details

Main Idea


7 ?

12 - 7 5

Difference between 12 and 7.


Doubles for Subtraction

TEKS:1.3B use objects and pictorial models to solve word problems involving joining, separating, and comparing sets within 20 and unknowns as any one of the terms in the problem such as 2 + 4= ?; 3 + ? = 7; and 5=? +51.3E explain strategies used to solve addition and subtraction problems up to 20 using spoken words, objects, pictorial models, and number sentences

Materials:Unifix cubesPractice problemsPlastic moneyDoubles +2 Four Step Practice Sheet (resources)

Instruction:Mathematicians, help me solve this problem:Mr. Teacher has two teams in his class. He asked Team A to solve 14 + 2. He asked Team B to solve 2 + 14. What answers did the two teams get? Why? Turn and tell your partner what you are thinking.Ask one student to show the class 14 + 2 with red and blue unifix cubes. Ask another student to show the class 2 + 14 with the same blue and red unifix cubes. Why are both sets equal to 16?They do not need to know that this is the commutative property, but understanding of the property will be developing.

Boys and girls, you have learned so many different strategies for adding and subtracting. One of my favorites is doubles! Let’s review our doubles facts. Begin, 2+2, 3+3, and continue to 9 + 9. We should also use those facts for subtraction problems. Knowing your doubles facts will help you solve problems quickly!

I have 16 markers and crayons in my school bag. 8 are crayons. How many are markers? Well, I know the answer is 8 because I know that 8 + 8= 16 so 16- 8 will also be 8. Have a volunteer come to the front of the class and confirm this with unifix cubes. Have them count two stacks of 8 and then break the stack of 16 in two stacks of 8.

Practice several more problems, each time having a student confirm by adding and then subtracting the doubles facts.It helps to show the two equal stacks of unifix cubes put together and taken apart to show the part-part whole bonds of doubles facts.


Ann has 14 pets. She has 7 gerbils. How many other pets does she have?

Joe ate 6 popsicles. 3 were cherry. How many were lime?

Marcos lost 18 baby teeth. 9 permanent teeth grew back in. How many teeth is he still missing?

Group #1: (Partner) Practice counting money with a partner

Group #2 (Independent) Doubles facts practice sheet

Group #3 (Teacher directed-Small group) Solve several subtraction problems using the 4-step process and doubles facts.



Using a Number Line for Subtraction

TEKS: 1.3B use objects and pictorial models to solve word problems involving joining, separating, and comparing sets within 20 and unknowns as any one of the terms in the problem such as 2 + 4= ?; 3 + ? = 7; and 5=? +51.3E explain strategies used to solve addition and subtraction problems up to 20 using spoken words, objects, pictorial models, and number sentences1.3F generate and solve problem situations when given a number sentence involving addition or subtraction of numbers within 20

Materials:Large floor number lineCountersIndex cardNumber cubesTape (to make partner number lines) or number lines

Instruction:

Have a large number line taped out on the floor in the front of your classroom. Display a subtraction example such as 8 – 3 = __, and call on a volunteer to tell a number story that would fit that subtraction situation. Then ask: How can we find the difference using the number line? Guide a volunteer to stand on the 8 and "hop" back three spaces on the number line. Ask the volunteer to tell his or her present position. [5] You may wish to encourage them to count backward as each hop is made. Ask for volunteers to record what happened on the number line writing the equation on the board.

Then encourage them to tell a subtraction story that describes the moves for 9 - 5. [If you start at 9 and take 5 hops backward, you land on 4.] Remind the students that, spaces, not points, are counted in operations on the number line.

After the class has seen several examples, place the students in pairs and give each pair a counter, a number cube, a set of index cards numbered to 10, and a strip of masking tape to write numbers on to use as a number line. You may want to write the numbers on the tape for them ahead of time.

Ask the students to take turns with one student showing an index card and rolling a number cube and the second student making up a subtraction story with the numbers from the card and the number cube. Then have the second student move a counter on the number line to find the difference of the smaller number from the larger number. Ask the first student to record the hops in pictures related to the story and in two other


forms. Then have the students switch roles. Encourage the students to predict the differences before they verify their predictions by moving a counter on the number line.

When the pairs have finished, call the class together to share some of the problems they wrote and tell how they found and recorded the differences. Then pose this problem:

I am the number you land on when you start at 4 and hop back 2--what am I?

Ask for volunteers to create similar problems and other volunteers to find their answers by using the large number line.

Practice:

Group #1: Independent- Mixed practice problems

Group #2: Partners- Review tubs

Group #3: Small Group Instruction- Continue solving subtraction problems using the number line.


Practice -Subtraction (Missing Part)

1. John put 11 two-color counters on the table. Six of them show the red side. How many of the counters show the yellow side?

2. Mary has 12 friends. Seven of her friends are girls. How many friends are boys?


3. Mrs. Palmer baked 15 cookies for her family. Seven of the cookies were chocolate chip. How many cookies were not chocolate chip?

4. Fourteen students are waiting at the water fountain. Nine are wearing tennis shoes. How many students are wearing other shoes?


5. Mark saw 13 dogs in his neighborhood. Six dogs were brown. How many dogs were not brown?

6. Marci used 16 beads to make a necklace. Eight beads were red. How many beads were other colors?


7. Pam has 11 plastic insects in her treasure box. Four of them are grasshoppers. How many insects are NOT grasshoppers?

8. Andy has 16 bugs. Nine of the bugs are bees. How many bugs were NOT bees?



1.

Mother made 8 cookies.

Bob ate 3 cookies.

How many cookies are left?

2.

Andy picked 15 apples.

Eight of the apples were green.

How many of the apples were not green?

3.

Six apples were in the bowl on the table.

Eight bananas were in the same bowl.

How many more

bananas than apples were

in the bowl?

4.

The baker made 13 cupcakes.

He sold 8 cupcakes.

How many cupcakes did he

have left?

5. Andre ate three carrots for

lunch and five carrots for dinner.

How many carrots did he eat?

6.Dad drank 5 sodas.

He drank 3 more sodas.

How many sodas did he drink?

Mixed Practice Problems

1. Nine boys and girls are playing ball. Six are boys. How many girls are playing ball?

A. 3 B. 4 C. 6

2. Jim’s dog had 7 puppies. He gave 5 of them away. How many puppies does he have left?

A. 2B. 5 C. 7

3. Jim saw 5 bees.CFISD TN 15-16 Addition and Subtraction within 20 29

Andy saw 8 bees.

How many bees did the 2 boys see?

A. 3B. 13C. 14

4. Meg had two pennies. John had 3 pennies.

How many pennies did they have together?

5. Mario had 9 jacks. He lost some jacks and now he has 2 jacks. How many jacks did he lose?


A. 11 B. 7 C. 6

6. Rodney had 15 balloons.

Six balloons flew away.

How many balloons did NOT fly away?

A. 9 B. 10 C. 21

7. Six rabbits are playing.

Three rabbits are eating.


Which number sentence shows how many rabbits there are altogether?

A. 9 – 6 = 3B. 6 + 3 = 9C. 9 + 3 = 12

8. Ten birds are singing. Six birds fly away.

Which number sentence shows how many birds are singing now?

A. 10 + 6 = 16B. 10 – 6 = 4C. 16 – 6 = 10D. 6 + 4 = 10

9. Four frogs are jumping.

Three frogs are eating.

Two frogs are swimming.


How many frogs in all?

A. 4 + 3 = 7B. 4 + 3 + 2 = 9C. 3 + 2 = 5D. 4 – 3 = 1

10. Twelve dogs are barking.

Five dogs run off.

How many dogs are left?

A. 5 + 7 = 12B. 12 + 2 + 5 = 19C. 5 + 2 = 7 D. 12 – 5 = 7

11. Jackson saw 5 big dogs and 9 little dogs. How many more little dogs than big dogs did he see?

A. 4B. 14C. 15D. 16


12. Jazmine gave 9 flowers to her mom.She gave her friend 6 flowers. How many flowers did she give away?

A. 2B. 15C. 18


Documents

storage.schoolnet.comstorage.schoolnet.com/cfisd/MATH_1_A_14 A... · Web viewCFISD First Grade Math. ... and comparing sets within 20 and unknowns as any one of the terms in the