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.

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.

why does it add when it says to subtract?

When you have a double negative, or two negatives in a row, it is the same as having a positive. 2+2 = 2-(-2) there are two negatives in a row so it becomes positive.

how do you add a negative and a negative together

to add a negative number to a negative number you ignore the negative signs and then add them. then you put the negative signs back. umm yea thats it.

so two negatives make a positive

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.

Main content

7th grade

Course: 7th grade > Unit 3

Lesson 4: Subtracting negative numbers fluently

Subtracting negative numbers review

Google Classroom

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 - 7 = - 5 + (- 7)

10 - (- 3) = 10 + 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 - (- 6) = - 5 + 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 - 7 = - 4 + (- 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

Want to learn more about subtracting negative numbers? Check out this video.

Practice

Problem 1

Subtract.

- 8 - (- 2) =

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

Want to join the conversation?

Sort by:

hesasoccerplayer
Posted 7 years ago. Direct link to hesasoccerplayer's post “why does it say subtract ...”
why does it say subtract when you have to add
Button navigates to signup pageComment on hesasoccerplayer's post “why does it say subtract ...”
(273 votes)
Answer
- Goldstein
  Posted 5 years ago. Direct link to Goldstein's post “Because two negatives equ...”
  Because two negatives equal a positive in a subtraction when it's next to each other. 3-(-6)=9=3+6=9
  Comment on Goldstein's post “Because two negatives equ...”
  (120 votes)
mysticeye8206
Posted 6 years ago. Direct link to mysticeye8206's post “Negative minus a positive...”
Negative minus a positive is a negative?
Button navigates to signup pageComment on mysticeye8206's post “Negative minus a positive...”
(76 votes)
Answer
- Nicholas
  Posted 6 years ago. Direct link to Nicholas's post “Yes, subtracting a positi...”
  Yes, subtracting a positive always makes the number smaller.
  Comment on Nicholas's post “Yes, subtracting a positi...”
  (57 votes)
Drew Creeger
Posted 6 years ago. Direct link to Drew Creeger's post “So basically 2 negatives ...”
So basically 2 negatives make a positive?
Button navigates to signup pageComment on Drew Creeger's post “So basically 2 negatives ...”
(58 votes)
Answer
- Xiran Bo
  Posted 2 years ago. Direct link to Xiran Bo's post “You could be mistaking th...”
  You could be mistaking this for a multiplication problem. negative * negative = positive but in addition negative + negative = negative.
  Comment on Xiran Bo's post “You could be mistaking th...”
  (15 votes)
Nasir
Posted 5 years ago. Direct link to Nasir's post “So, correct me anyone if ...”
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?
Button navigates to signup pageComment on Nasir's post “So, correct me anyone if ...”
(32 votes)
Answer
- Gracie
  Posted 2 years ago. Direct link to Gracie's post “Yes that is correct.”
  Yes that is correct.
  Comment on Gracie's post “Yes that is correct.”
  (7 votes)
The Abandoned
Posted 6 months ago. Direct link to The Abandoned's post “can 10 people please vote...”
can 10 people please vote me i want the moon badge to
Button navigates to signup pageComment on The Abandoned's post “can 10 people please vote...”
(28 votes)
Answer
Ton, Quan
Posted 4 years ago. Direct link to Ton, Quan's post “I am confused that 8 - (-...”
I am confused that 8 - (-2) means you add up. IS that count Mr.Khan?
Button navigates to signup pageComment on Ton, Quan's post “I am confused that 8 - (-...”
(17 votes)
Answer
- summerdean66
  Posted 4 years ago. Direct link to summerdean66's post “Because when you do a sub...”
  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.
  Comment on summerdean66's post “Because when you do a sub...”
  (12 votes)
Shelby
Posted 3 years ago. Direct link to Shelby's post “so two negatives make a p...”
so two negatives make a positive
Button navigates to signup pageComment on Shelby's post “so two negatives make a p...”
(5 votes)
Answer
- Ian Pulizzotto
  Posted 3 years ago. Direct link to Ian Pulizzotto's post “It depends on the operati...”
  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.
  Comment on Ian Pulizzotto's post “It depends on the operati...”
  (6 votes)
fjones
Posted 5 years ago. Direct link to fjones's post “why does it add when it s...”
why does it add when it says to subtract?
Button navigates to signup pageComment on fjones's post “why does it add when it s...”
(13 votes)
Answer
- Madeleine
  Posted 5 years ago. Direct link to Madeleine's post “When you have a double ne...”
  When you have a double negative, or two negatives in a row, it is the same as having a positive.
  2+2 = 2-(-2) there are two negatives in a row so it becomes positive.
  Comment on Madeleine's post “When you have a double ne...”
  (10 votes)
Yousuf
Posted 7 months ago. Direct link to Yousuf's post “pls help me get ten votes...”
pls help me get ten votes for moon badge
Button navigates to signup pageComment on Yousuf's post “pls help me get ten votes...”
(19 votes)
Answer
27warfielda
Posted 7 months ago. Direct link to 27warfielda's post “how do you add a negative...”
how do you add a negative and a negative together
Button navigates to signup pageComment on 27warfielda's post “how do you add a negative...”
(13 votes)
Answer
- amaury lopez
  Posted 7 months ago. Direct link to amaury lopez's post “to add a negative number ...”
  to add a negative number to a negative number you ignore the negative signs and then add them. then you put the negative signs back. umm yea thats it.
  Button navigates to signup page
  (13 votes)