How to Make Calendar Dice

Calendar dice are a pair of cube dice numbered so that every date from 1 to 31 can be represented by two faces. For every day that passes, the dice are rotated so that the correct date is shown on the top faces of the cubes.

You can also include a dodecahedron (12-sided dice) that is labeled with each month to make an elegant 3-piece calendar.

Difficulty: Moderately Easy

Instructions

Things You'll Need:

• two blank cubes and a blank dodecahedron.
• Wooden dice can be found in craft stores. Or, you can make your own out of stiff paper and fill figures with beads to give them weight.

1. First, label the 12 faces of the dodecahedron. You can either use the numbers 1 through 12, or you can use the 3-letter abbreviations for the names of the months.

2. 
    

   Next, label the faces of the two cubes so that the digits on each face can be arranged to make every number from 1 to 31. On one of the die, label faces with the digits 0, 1, 2, 3, 4, and 5. On the other die, label the faces with the digits 0, 1, 2, 6, 7, and 8. Be sure to make a 6 that can be inverted to look like a 9. Click to enlarge thumbnail.

3. The table given in the figure at left shows how every number from 1 to 31 can be made out of the digits on these dice. Since the 6 and 9 are invertible, you can distinguish between the 16th and the 19th of the month by how you orient the dice.

4. A set of calendar dice make a great gift, and making them is also a fun math project for kids.