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## 'Prompt Cards' printed from http://nrich.maths.org/

## Prompt Cards

Can you work out what Charlie's number is from these clues?

- C1: Charlie's number is palindromic, the second and third numbers are different.
- C2: Charlie's number is greater than 100 and is prime.
- C3: Charlie's number is odd. The difference between the largest and smallest digits is 5.
- C4: Charlie's number is less than 1000. The sum of the digits is 14.
- C5: Charlie's number is not divisible by 3. It is less than 500.
- C6: Charlie's number is a whole number with only two divisors.

Now can you make this tower from coloured cubes? Or, if you don't have any cubes, you could draw it.

- C1: There are six blocks in the tower, a yellow one is at the top.
- C2: The red block is above the green block.
- C3: One of the yellow blocks is above the green block, the other is below it.
- C4: Each of the blue blocks shares a face with the green block.
- C5: No two blocks of the same colour touch each other.
- C6: There are no brown blocks in the tower.

These clues could be typed out onto index cards and given to a group of children.Similarly, almost any shape/solid that is constructed can be represented as a set of clues for children to work with. En route, an opportunity to develop listening skills, a reasoning facility, as well as encourage the thoughtful selection and discrimination of materials.