Mathematics

Jacey Lester

22 August, 17:55

Here's another way to think about the number line model for 2 - (-3) : if we were adding 2 + (-3), we'd first move two units to the right. Then, we'd move three units to the left, because we move left when adding negative integers. But instead, we're subtracting - 3. Addition and subtraction are inverse operations, or opposite operations; they undo one another. So we move in the opposite direction, right, and end up with a sum of 5. As a result, the number line models for 2 - (-3) and 2 + 3 are identical. This shows that subtracting a negative integer is the same as adding a positive integer.

Subtracting - 9 from any number is the same as

A

subtracting 9 from that number.

B

subtracting 0 from that number.

C

adding 9 to that number.

D

adding - 3 to that number.