# Subtracting negative numbers review

CCSS Math: 7.NS.A.1c
Review the basic of subtracting negative numbers and try some practice problems.

## Subtracting negative numbers

Subtracting a number is the same as adding the opposite of the number.
Let's look at two examples:
$-5\goldD{-7} = -5\goldD{+(-7)}$
$10\goldD{-(-3)}=10\goldD{+3}$
Note: In both examples, we change subtraction to addition and changed the sign of the second number to the opposite sign.
Want to know why this works? Check out this video.
Once we have an addition problem, we can solve.

### Example 1: negative $-$ negative

Lets subtract $-5-(-6)$.
Step 1: Rewrite as an addition problem
$-5\goldD{-(-6)}=-5\goldD{+6}$
Step 2: Start at the first number in the addition problem, in this case $-5$:
Step 3: Move $6$ places to the right. We move $6$ to the right because adding positive $6$ increases our number by $6$.
$-5+6$ takes us to $1$ on the number line.
$-5-(-6)=1$

### Example 2: negative $-$ positive

Lets subtract $-4-7$.
Step 1: Rewrite as an addition problem
$-4\goldD{-7}=-4\goldD{+(-7)}$
Step 2: Start at the first number in the addition problem, in this case $-4$:
Step 3: Move $7$ places to the left. We move $7$ to the left because adding negative $7$ decreases our number by $7$.
$-4+(-7)$ takes us to $-11$ on the number line.
$-4-7=-11$
$-8-(-2)=$