6th Grade Math Textbook, Fundamentals

 &KDSWHU

1-3

Key Concept

Add Integers with Like Signs

• Add the absolute values of the addends.


• Use the sign of the addends for the sum.

Add: 67  29

| 67|| 29| Add the absolute values.

67  29

96

So 67  29 96. Both addends are

positive, so the

sum is positive.

1 Add:  5 (9) (16)

[ 5 (9)](16)

 14 (16) Add.

 30

So  5 (9) (16) 30.

Add from left

to right.

Both addends are

negative, so the

sum is negative.

2

Update your skills. See page 409 VI.

Add Integers

Objective To model addition of integers• To add integers with like and

unlike signs• To add more than two integers

Kyle lost 5 points in the first round of an electronic game

and lost 3 points in the second round. What was the total

number of points Kyle lost after two rounds? What integer

represents the loss?

To find the total points lost, add:  5 (3)

You can use tiles and a number line to add integers

with like signs.

Add:  5 (3)

Kyle lost a total of 8 points after two rounds.

The integer representing this loss is 8.

You can also use absolute value to add integers with like signs.

Method 1 Use Tiles

• Model each addend.
  
   5  (3)


• Join the tiles.

 8

Let 1.

Add:  58 (31)

| 58 || 31 |

58  31

89

So  58 (31) 89. Both addends are negative,

so the sum is negative.

Method 2 Use a Number Line

• Start at zero.


• Move left to add negative integers.

 5 (3)  8