Combinations

problem
Flora the florist

Age

14 to 16

Challenge level

Flora has roses in three colours. What is the greatest number of identical bunches she can make, using all the flowers?
problem
Spectrometry detective

Age

16 to 18

Challenge level

From the atomic masses recorded in a mass spectrometry analysis can you deduce the possible form of these compounds?
problem
Elevenses

Age

11 to 14

Challenge level

How many pairs of numbers can you find that add up to a multiple of 11? Do you notice anything interesting about your results?
problem
Trominoes

Age

11 to 16

Challenge level

Can all but one square of an 8 by 8 Chessboard be covered by Trominoes?
problem
Coins

Age

11 to 14

Challenge level

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

Age

11 to 18

Challenge level

Four friends must cross a bridge. How can they all cross it in just 17 minutes?
problem
Move a match

Age

7 to 11

Challenge level

How can you arrange these 10 matches in four piles so that when you move one match from three of the piles into the fourth, you end up with the same arrangement?
problem
Royal arm wrestling

Age

11 to 14

Challenge level

How many arm-wrestles will there be in the royal arm wrestling championship?
problem
Making 11p

Age

11 to 14

Challenge level

How many ways are there to make 11p using 1p, 2p and 5p coins?
problem
Four-triangle arrangements

Age

5 to 7

Challenge level

How many different shapes can you make by putting four right- angled isosceles triangles together?