Question

On the number line below, the numbers a and b are the same distance from 0. What is a + b? Explain how you know.​

Answer 1

If we start at zero and move a units to the right, and then move the same number of units to the left, we will be back at 0. We can also represent this symbolically. Since a and b are the same distance from zero but are on opposite sides of zero, we know that they are opposites, so b = -a.

Answer 2

If we start at zero and move a units to the right, and then move the same number of units to the left, we will be back at 0. We can also represent this symbolically. Since a and b are the same distance from zero but are on opposite sides of zero, we know that they are opposites, so b = -a