Main content

### Course: 7th grade > Unit 3

Lesson 4: Subtracting negative numbers fluently# 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:

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

Step 2: Start at the first number in the addition problem, in this case $-5$ :

Step 3: Move $6$ places to the $6$ to the $6$ .

**right**. We move**right**because**adding positive**$6$ increasesour number by### Example 2: negative $-$ positive

Lets subtract $-4-7$ .

Step 1: Rewrite as an addition problem

Step 2: Start at the first number in the addition problem, in this case $-4$ :

Step 3: Move $7$ places to the $7$ to the $7$ .

**left**. We move**left**because**adding negative**$7$ decreasesour number by*Want to learn more about subtracting negative numbers? Check out this video.*

## Want to join the conversation?

- why does it say subtract when you have to add(303 votes)
- Because two negatives equal a positive in a subtraction when it's next to each other. 3-(-6)=9=3+6=9(144 votes)

- Negative minus a positive is a negative?(82 votes)
- Yes, subtracting a positive always makes the number smaller.(73 votes)

- So basically 2 negatives make a positive?(65 votes)
- You could be mistaking this for a multiplication problem. negative * negative = positive but in addition negative + negative = negative.(20 votes)

- 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?(41 votes)- Yes that is correct.(16 votes)

- why do you need votes?(27 votes)
- It's

1. So people don't repeat posts, instead upvoting them, letting people know that they agree.

2. It helps with a few badges in Khan Academy(20 votes)

- I am confused that 8 - (-2) means you add up. IS that count Mr.Khan?(20 votes)
- 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.(13 votes)

- This is very confusing.(20 votes)
- so two negatives make a positive(10 votes)
- It depends on the operation.

Adding two negatives always makes a negative.

Subtracting two negatives could make zero, a negative, or a positive depending on how the two negatives compare to each other.

Multiplying or dividing two negatives always makes a positive.(10 votes)

- I don't get why they are swiching the signs telling me to add when I have to subtract. I just don't understand at all.(12 votes)
- Another way to think of a negative sign is as an OPPOSITE sign. So when you are subtracting a negative, it's really telling you to do the opposite of subtracting, which ends up being adding.

Another way some people might look at it is to think of someone telling you that you no longer owe them any money you borrowed. By taking away your debt (subtracting a negative), they have given you a gift (adding a positive).(29 votes)

- how do you add a negative and a negative together(17 votes)
- for example, if it's -2 + -2, remove the negative signs, now it's 2+2. 2+2 = 4. Now add the negative sign back. Now it's -4.(5 votes)