# Two-Cube Calendar

Initializing live version

Requires a Wolfram Notebook System

Interact on desktop, mobile and cloud with the free Wolfram Player or other Wolfram Language products.

Each face of two cubes is labeled with a single digit from 0 to 9. It is possible to show any date from 01 to 31 on the front faces. The problem is to determine the sum of the digits that cannot be seen.

[more]
Contributed by: Izidor Hafner (August 2013)

Open content licensed under CC BY-NC-SA

## Snapshots

## Details

Each cube must have faces with 0, 1, and 2, leaving six faces with 3, 4, 5, 6, 7, 8; the face with 6 can be turned upside down to be 9.

Reference

[1] M. Gardner, *The Colossal Book of Short Puzzles and Problems*, New York: W. W. Norton, 2006 pp. 4, 18.

## Permanent Citation