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Lesson 2: Intro to subtracting negative numbers

# Subtracting negative numbers review

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:
minus, 5, start color #e07d10, minus, 7, end color #e07d10, equals, minus, 5, start color #e07d10, plus, left parenthesis, minus, 7, right parenthesis, end color #e07d10
10, start color #e07d10, minus, left parenthesis, minus, 3, right parenthesis, end color #e07d10, equals, 10, start color #e07d10, plus, 3, end color #e07d10
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 $-$minus negative

Lets subtract minus, 5, minus, left parenthesis, minus, 6, right parenthesis.
Step 1: Rewrite as an addition problem
minus, 5, start color #e07d10, minus, left parenthesis, minus, 6, right parenthesis, end color #e07d10, equals, minus, 5, start color #e07d10, plus, 6, end color #e07d10
Step 2: Start at the first number in the addition problem, in this case minus, 5:
Step 3: Move 6 places to the right. We move 6 to the right because adding positive 6 increases our number by 6.
minus, 5, plus, 6 takes us to 1 on the number line.
minus, 5, minus, left parenthesis, minus, 6, right parenthesis, equals, 1

### Example 2: negative $-$minus positive

Lets subtract minus, 4, minus, 7.
Step 1: Rewrite as an addition problem
minus, 4, start color #e07d10, minus, 7, end color #e07d10, equals, minus, 4, start color #e07d10, plus, left parenthesis, minus, 7, right parenthesis, end color #e07d10
Step 2: Start at the first number in the addition problem, in this case minus, 4:
Step 3: Move 7 places to the left. We move 7 to the left because adding negative 7 decreases our number by 7.
minus, 4, plus, left parenthesis, minus, 7, right parenthesis takes us to minus, 11 on the number line.
minus, 4, minus, 7, equals, minus, 11

## Practice

Problem 1
• Current
Subtract.
minus, 8, minus, left parenthesis, minus, 2, right parenthesis, equals

Want to try some more subtracting negative numbers problems? Check out this exercise.

## Want to join the conversation?

• why does it say subtract when you have to add
• Because two negatives equal a positive in a subtraction when it's next to each other. 3-(-6)=9=3+6=9
• Negative minus a positive is a negative?
• Yes, subtracting a positive always makes the number smaller.
• So basically 2 negatives make a positive?
• You could be mistaking this for a multiplication problem. negative * negative = positive but in addition negative + negative = negative.
• So, correct me anyone if I'm wrong. So let's say I have
-4-(-4), wouldn't equal 0? Because instead of me subrtracting with -4, I have to add it. So, would it be 0 instead of -8?
• Yes that is correct.
• i will still vote
• I am confused that 8 - (-2) means you add up. IS that count Mr.Khan?
• Because when you do a subtraction problem with a positive taken away, you go down. 8 - 2 = 6 When that's negative, you have the opposite, so you go up. 8 - ( - 2 ) = 10 You still might wonder why it isn't - 10, but I can answer it. Subtraction and addition like this stuff are never gonna give you negative.