Prime numbers

The flow chart requires two numbers, M and N. Select several values for M and try to establish what the flow chart does.

A man has 5 coins in his pocket. Given the clues, can you work out what the coins are?

Show that it is rare for a ratio of ratios to be rational.

Using your knowledge of the properties of numbers, can you fill all the squares on the board?

Take any pair of numbers, say 9 and 14. Take the larger number, fourteen, and count up in 14s. Then divide each of those values by the 9, and look at the remainders.

Use cubes to continue making the numbers from 7 to 20. Are they sticks, rectangles or squares?

Weekly Problem 24 - 2006
How many of the rearrangements of the digits 1, 3 and 5 give prime numbers?

Can you make lines of Cuisenaire rods that differ by 1?

Which of the numbers shown is the product of exactly 3 distinct prime factors?

Can you work out what step size to take to ensure you visit all the dots on the circle?