Chapter 9 · Questions · page 41 of 68
How do you subtract a negative number?
Short answerSubtracting a negative is the same as adding a positive. 7 - (-3) becomes 7 + 3, which is 10.
levelPre-algebra
standard7.NS.A.1
practiceInteger operations
Subtracting means adding the opposite. The opposite of -3 is 3, so taking away -3 adds 3. The two minus signs side by side become one plus.
How to use it
- Change the subtraction to addition.
- Change the number after it to its opposite.
- Add with the signed-number rules.
Example
Where it goes wrong
- Treating 7 - (-3) as 7 - 3.
- Flipping the sign of the first number too. Only the number being subtracted changes.