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GeoGebraGeoGebra Classroom

Applets for understanding Div and Mod

1. Div and Mod.

This applet has a few parts for you to play with. In the two input boxes:
  • can be any integer
  • can be any positive integer
You can also pan, zoom, and move red things.
In the number line applet above, LOOK and PLAY in order to decide how the following things are related. First try to relate 1 to 2, then 2 to 3, and so on--but eventually you'll want to be able to go from 1 right to 5.
  1. The values of and in the input boxes
  2. The green dots shown on the number line, and the numbers above and below them
  3. The zone number (that's not official language, by the way--it's just to help you notice things)
  4. The red circle and arrow, and the equation above them
  5. The two equations next to the input boxes

Test your understanding!

Without touching the applet, choose integer values for and , with . Enter them here.

Make your predictions. What values will div and mod take?

Enter your chosen values of and into the applet. Were you right?

2. Just Mod.

We can wrap the number line around a circle to make a "clock".
  • Blue buttons control the greatest label (right end).
  • Green buttons control the least label (left end).
  • Each square button resets a label to 0.
  • The "modulus" slider chooses how many "hours" are on the clock.
  • Use the other sliders to make the labels easier to read.
Play and notice for a few minutes on your own.

Build understanding.

Choose an integer from 2 to 20 for the modulus, . Enter it here and in both applets.

Pick any "hour" on the clock applet. List the numbers you find there. (Use the blue and green buttons to extend the range of values, if needed, so that you have at least three numbers.)

Use each of those numbers for in the number line applet. What do you notice?

Video play-through of this activity: https://youtu.be/UNCGqcGR3O4