Master the 7 pillars of school success

(+) + (-) = Take the sign of the largest number

(-) + (-) = -

1. When  adding sign numbers with the same sign, you add the numbers, and keep the same sign.

For example: 3+3= 6   -4+-3= -7

This shortcut was demonstrated with the numberline.

2. When you have different signs, you subtract and keep the sign of the number you have "more" of.

For example: -7 +3 = -4   ( you have more -7's than 3's )
​                          -4 + 8 = 4 ( you have more 8's than -4's)

This shortcut was demonstrated with the "coin" activity.

### You can use coins to illustrate how to add a positive and negative number

positive numbers

Tails represent negative numbers

2.The positive and negative numbers pair up, and cancel each other out.
3. After cancelling out you are left with two coins tails side up. Tails represent negative numbers so the answer equals -2

Tails
Tails
Tails
4 +   (-6)
-2
When you add a positive number on a number line you move to the right. You start at the first number, and move to the right.

For example 4+5
Start at 4 and move 5 places to the right, which equals 9
-6 + 8
Start at -6 and move 8 places to the right, which equals 2

When you add a negative number, you do the opposite. You move to the left on the number line.
4 +(-6)
Start at 4 and move 6 places to the left, which equals -2
-1 +(-3)
​Start at -1 and move 3 places to the left, which equals -4

# Adding Positive and Negative Numbers

Examples

5 + (-3) =

-6 + 3 =

-7 + (-2) =

65 +(-20) =

-45 + 42 =
When you add positive and negative numbers it can be confusing trying to figure out if the answer should be positive or negative. Before we go over two shortcuts for adding negative numbers, let's look at two visual examples that illustrate what is happening when adding these numbers.