Department of EducationDIVISION OF LEGAZPI CITYLegazpi City

Learning Action Cell (LAC Session)

Albay Central SchoolLegazpi CityMATHEMATICS Grade 3 & 4What are the difficulties in teaching multiplication in grade 3 and 4?

Numbers are the foundation of mathematics and student must learn counting and acquire instant recall of the single digit number facts for addition and multiplication and the related facts for subtraction and division.

Whole number operations the addition, subtraction; multiplication and division of whole numbers represent the basic operations of mathematics. Much of mathematics is a generalization of these operations and rests on an understanding of these procedures. They must be learned with fluency using standard algorithms.

Reminders:

Mathematics is not a collection of unrelated topics. Mathematics is hierarchical. All of the topics discussed fit into an interconnected dependency pattern. These dependencies form a structure.

This structure is really part of the content of mathematics and was built by mathematical reasoning and it takes mathematical reasoning to make sense of the structure. The very structure of mathematics dictates that certain topics must be mastered before any understanding of the next topic can even be hoped for.

The following are problem solving exercises which are meant to keep you on your toes and show that Mathematics can be fun and exciting. THIS IS NOT A TEST YOUR ABILITY AND SKILL IN MATHEMATICS.

If there are fifteen crows in the fence and the farmer shoots a third of them, how many are left? ___2 . How many times can you subtract the number 5 from 25? ______3. How much dirt is in a hole that 3 feet deep and 6 inches in diameter? _____4. On my way to the fair, I met 7 jugglers and a bear. Every juggler had 6 cats, every cat has 5 rats, every rat had 4 houses, every house had 3 mice, every mouse had 3 lice, every louse had a spouse. How many are going to the fair? ______5. Johnnys mother had four children. The first was April, the second was May and the third was June. What was the name of the fourth child? ______6. What months has 28 days? _______7. How many animals of each species did Adam take with him on the ark? _____8. If three cats can kill 3 rats in 3 minutes in 3 minutes, how many cats will take to kill 3 rats in 30 minutes? _______8

9. Peter had a dozen mangoes in his office. He ate all but 8. How many were left? _______10. There are five oranges in the basket. How will you distribute the oranges to five people, such that one orange is still left in the basket? ______________11. What number leaves you nothing if you cut it half? _______12. A peacock lays 10 eggs in a day. How many eggs will it lay in 10 days? ______13. A man sold a carabao at Php 1000 bought it back at Php 2000, sold it at Php 3000, bought at Php 4000 and sold at Php 5000. How much did he gain? _____14. What is the beginning of eternity, the end of time, the beginning of every end, and the end of every place? _______15. How can you find the quotient and remainder of 179 divided by 11 on a calculator without using the division key? __________Fill in the blanks below to make the sentences true.

a. Equal groups of =

b. + + =

c. x =

a. Equal groups of =

b. + + =

c. x =

____ Rows of ____ = ______

____ columns of _____ = ______

____ + ____ + ____ + ____ = _____

____ + ____ + ____ + ____ + _____ = ____

_____ x ____ = ______ Use skip counting on the number line to find the product (the result of multiplying).

5 x 6

2 x 4

3 x 5

5 x 6 = 30

Multiplication Facts Strategies Complexity=1, Mode=2,5,10

Answer the following problems from memory.

1. 2 x 8 =

2. 5 x 6 =

3. 5 x 10 =

Complexity=1, Mode=9

Answer either from memory or by applying strategies. 9 x 3 =

2. 9 x 8 =Solution

When multiplying by 9, subtract your digit by 1 to get the tens digit.So 3 - 1 = 2.The sum of the digits in your answer adds up to 9. So if the tens digit is 2, then the ones digit is 9 - 2 = 7.Therefore, your answer is 27

Alternate strategy:

When multiplying by 9, just multiply by 10 and subtract the number. In this case, we have3 9 =3 10 - 3 =30 - 3 =27

Alternate strategy: Put both hands in front of you with all 10 fingers out. Take finger #3 and curl it. You'll see 2 fingers to your left and 7 fingers to your right. See how this gives you the answer of 27?

Complexity=1, Mode=4 Answer either from memory or by applying strategies.

1. 4 x 6 = 2. 4 x 4 =

SolutionTo multiply by 4, multiply by 2, then multiply by 2 again.6 2 2 =12 2 =24

SolutionTo multiply by 4, multiply by 2, then multiply by 2 again.4 2 2 =8 2 =16Complexity=1, Mode=6Answer either from memory or by applying strategies.

1. 5 x 6 = 2. 4 x 6 =

SolutionTo multiply by 6, multiply by 5 and add the number.5 6 =5 5 + 5 =25 + 5 =SolutionTo multiply by 6, multiply by 5 and add the number.4 6 =4 5 + 4 =20 + 4 =24 MULTIPLICATION TRICKSMULTIPLICATION NEAREST TO 100

EX. 98 X 97 = 9506

98-3 = 9597-2 = 952 x 3 = 062 x 3 = 06

Try these93 x 92 =6. 85 x 98 =96 x 94 =7. 65 x 97 =92 x 97 =8. 88 x 88 =95 x 99 =9. 86 x 91 =

2-3

Multiplying 2 digits by 2 digit numbers. Using Cross and vertical Method.

Ex. 45 x 36 1 23 93 0 3x4=12(3x5)+(4x6)5x6=30 1 6 2 0 15 + 24=39

Group Activity Multiplying 3 - 4 digits by 3 to 4 digit numbers. Using Cross and vertical Method. Show/draw pattern.

a. 385b. 641 x 642 x 433

c. 3431d. 5526 x 5243 x 4322

4 kinds of studentHe who Knows and Knows that he knowsHe is wiseFollow him

He who Knowsand knows not that he knowsHe is asleepAwake him

He who Knows notand knows that he knows notHe is a childTeach him

He who knows not and knows not that he knows notHe is a foolSHUN him

Which of these 4 should you take care of?