## Calendar Cubes

#### Problem

Two wooden cubes have digits painted on each face in such a way that it is possible to display any date of the month.

For example,

Show clearly how you would label each face to achieve this.

#### Solution

Clearly each cube must have 0, 1 and 2 painted on it. Leading to the solution.

Cube 1 | Cube 2 |

0 | 0 |

1 | 1 |

2 | 2 |

3 | 6 |

4 | 7 |

5 | 8 |

The trick being, the 6 can be turned around to make 9.

How would two wooden cubes be labelled to make all 2-digit primes?

(This time the 6 is different from the 9!)

Problem ID: 103 (Feb 2003) Difficulty: 2 Star