# Some Sums on the Number Line

- Author:
- bzahnerserp

## Introducing the Model

The dynamic number line shows the location of , , and 0. All of the other information has been hidden.
The three grey diamonds are located at , , and . Unfortunately, the labels are hidden! Using just the location of and , can you identify which point is , which is , and which is ? When you think you know the answers, click the buttons to show the labels.
This model is dynamic. You can move and . What do you notice when you move the points? What questions do you have?
For a hint, you can show numbers. For a challenge, try to solve this without showing the numbers!

## Let's Make it a Game!

Player 2 looks away.
Player 1 moves points and to a new location. Make sure the gray dots are all showing.
Then, Player 2 looks at the dots and tries to guess which diamond is , which is , and which is . Click the buttons to show the labels on each point.
What strategies can you use to guess correctly the first time?