# Number Line Addition

- Author:
- Dr. Doug Davis, 3D

- Topic:
- Addition, Numbers, Real Numbers

## Description

Two number lines are used to show addition of numbers, . One number line slides as the "a" value is changed and the second number line shows the "b" with the resulting "c" value shown on the "a" number line.

## Directions

This shows the addition of numbers where "a" and "b" are on separate real number lines.
The value of "a" can be changed with the slider, the entry box or moving the plus symbol.
The value of "b" can be changed with the "b" slider or the second entry box.
Describe what happens when "a" is less than 0.
Describe what happens when "b" is less than zero.
Can you find values of "b" for any value of "a" where the sum, "c" is zero?