Question

How do I add and subtract negative numbers?

Answer 1

to add a negative number, you subtract its positive equivalent. 3 + -3 is 3 - 3, which is 0.
to subtract a negative, you add. 3 - -3 is 3 + 3, which is 6.

Answer 2

Hi!

When adding and subtracting negative numbers, just imagine a number line.

For example, let's say we're adding 3 + -7.
Tip: Adding negative numbers is the same as subtracting positive numbers. So 3 + -7 is the same as 3 - 7.

Here's a numberline:

-10, -9, -8, -7, -6, -5, -4, -3, -2, -1, 0, 1, 2, 3, 4, 5
Now add 3 to negative 7. (or subtract 7 from 3)
-10, -9, -8, -7, -6, -5, -4, -3, -2, -1, 0, 1, 2, 3, 4, 5

3 + -7 = -4

Let's try subtracting now. How do we solve 5 - (-3)?
Tip: Subtracting a negative is the same as adding a positive. So 5 - (-3) is the same as 5 + 3. Another way of thinking of it, is two minuses make a positive.

Numberline:
-5, -4, -3, -2, -1, 0, 1, 2, 3, 4, 5
Subtract -3 from 5. (or add 12 to 5)
-5, -4, -3, -2, -1, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10

Here are a few more examples.

-7 + -3 (which is the same as -7 - 3) = -10
-8 + 6 = -2
-9 - (-8) (which is the same as -9 + 8) = -1
-9 - 3 = -12

Hope this helps! :)