SaiBook.us Algebra

Example

Title: Adding signed numbers

Grade: 6-a Lesson: S1-L2

Explanation: The best way to understand algebra is by looking at some examples. Take turns and read each example for easy understanding.

Examples:

Lets add -7 and +5.

Step 1a

Since one number is negative and the other is positive, we’ll use the different sign addition rule.

Explanation: \$|-7|\$ = 7 and \$|5|\$ = 5

\$7 - 5 = 2 \$.

Step 1b

The sign of the result will be the sign of the number with the larger absolute value, which in this case is

Explanation: Therefore, \$- 7 + 5 = - 2 \$.

Lets add +9 and -4

Step 2a

Since one number is positive and the other is negative, we’ll use the different sign addition rule.

Explanation: \$|+9|\$ = 9 and \$|-4|\$ = 4

\$9 - 4 = 5 \$.

Step 2b

The sign of the result will be the sign of the number with the larger absolute value, which in this case is

Explanation: Therefore, \$ + 9 + (- 4) = 5 \$.