The amazing Desmos can be used to create number lines for our upper elementary learners. After a few simple steps you can create a number line from a two-variable coordinate plane…
1. Access http://www.desmos.com.
2. Tap Graph Settings (the wrench tool) and uncheck the boxes for Grid and Y-Axis.
3. Check the box for Arrows.
4. Add the point (a,0).
5. Click the button to add a slider for a.
Press the play button and watch the point move between -10 and 10. These are the default values. You can adjust these values by clicking on the number and typing the value you prefer.
Now, the awesome part…
Press the pause button and ask what is the value? Or, given a specific number, place the point on the number line.
Zoom in and out to adjust the minimum and maximum values or tap on Graph Settings (the wrench tool) to adjust precisely.