Here are ten cards numbered 0 to 9:
Using all ten cards, rearrange them to make five prime numbers.
Can you find a way of doing it with five two-digit numbers?
How about using one one-digit number, one three-digit number and three two-digit numbers? ...
This problem is based on an idea from Mathematical Challenges for Able Pupils Key Stages 1 and 2, published by DfES.