1

Warm-up

Get your checklist from my desk.

Get out your homework.

Make sure it is done.

2

Pre-Algebra

Add Integers

3

What Are You Learning?

I CAN add integers.

4

Why Do You Need To Know This?

Adding integers is useful because it helps in solving real world problems.

5

Notes

What are opposites?

When you add 2 opposites, what is their sum?

Two integers that are opposites are also called additive inverses.

6

Adding Integers Same Sign

The sum of two positive integers is positive. The sum of two negative integers is negative.

Ex: -12 + (-31) = -43

7

-19 + (-7)

-26

-12 12 26

25% 25%25%25%

1. -26

2. -12

3. 12

4. 26

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20

21 22 23 24 25 26 27 28 29 30 31 32 33

8

Notes

Use tiles to find 2 + (-5)

□□ + ■■■■■

Group and remove the zero pairs.

□□ ■■■■■

Count the tiles you have left. ■■■ -3

2 + (-5) = -3

9

Adding Integers Different Signs

To add integers with different signs, subtract their absolute values and take the sign of the larger number.

Ex: 7 + (-18) = -11

10

Integer Song

Sing to the tune of “Row, Row, Row, Your Boat”

“Same sign, add and keep,

Different sign subtract.

Take the sign of the higher number,

Then you’ll be exact.”

11

Complete the following problems.

a. -1 + 4b. 7 + (-3)c. -2 + (-2)d. (-7) + 3

12

-54 + 45

-9 9-9

9 99

25% 25%25%25%

1. -9

2. 9

3. -99

4. 99

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20

21 22 23 24 25 26 27 28 29 30 31 32 33

13

10 + (-34) + 17

61 -41 41 -7

25% 25%25%25%

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20

21 22 23 24 25 26 27 28 29 30 31 32 33

1. 61

2. -41

3. 41

4. -7

14

Complete the following problems.

a. 2 + (-6)

b. -4 + 9

c. -5 + (-1)

15

At 4:00 a.m., the outside temperature was -28°. By 4:00 p.m. it rose 38 degrees. What was the temperature at 4:00 p.m.?

-66 10 -1

0 66

25% 25%25%25%

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20

21 22 23 24 25 26 27 28 29 30 31 32 33

1. -66

2. 10

3. -10

4. 66

16

-16 + (-56) + (-90)

-18

-162 18 -5

0

25% 25%25%25%

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20

21 22 23 24 25 26 27 28 29 30 31 32 33

1. -18

2. -162

3. 18

4. -50

17

Complete the following problems.

a. -37 + (-5)

b. 14 + (-4)

c. -20 + (-15)

d. -100 + 5 +(-3)

e. -7 + (-4) + 13 + (-5)

18

Complete the following problems.

a. -22 + (-16)

b. 60 + (-13)

c. -125 + 35

d. -12 + (-6) + 15 + (-2)

e. 1 + (-3) + 2 + (-10)

f. -250 + 200 + (-100)

19

Homework

Write the following assignment in your agenda!!

Sheet E-60