You may also like

Consecutive Numbers

An investigation involving adding and subtracting sets of consecutive numbers. Lots to find out, lots to explore.

Tea Cups

Place the 16 different combinations of cup/saucer in this 4 by 4 arrangement so that no row or column contains more than one cup or saucer of the same colour.

Counting on Letters

The letters of the word ABACUS have been arranged in the shape of a triangle. How many different ways can you find to read the word ABACUS from this triangular pattern?


Age 11 to 14 Short
Challenge Level

Pegs numbered $1$ to $50$ are placed in order in a line, with number $1$ on the left.

They are then knocked over, one at a time, following these rules:
  • Starting with the first standing peg on the left, alternate pegs are knocked down, until the end of the row is reached.
  • Each time the end of the row is reached, repeat the previous rule.
What is the number of the last peg to be knocked down?

If you liked this problem, here is an NRICH task that challenges you to use similar mathematical ideas.

This problem is taken from the UKMT Mathematical Challenges.
You can find more short problems, arranged by curriculum topic, in our short problems collection.