On the board, have a list of suspects such as Mr Jones and Lady Helena. Each one has an answer next to his or her name. Underneath, have a list of sums or problems that the pupils must answer - have one fewer question so a suspect is left over at the end.
Tell the pupils one of the characters has committed a crime, such as stealing diamonds, and they must find out who it is.
Pupils answer each question and each correct answer matches a suspect's answer that they can cross off. The character left out is the one whose answer hasn't come up. They are the ones who committed the crime.
This is good for problem solving, checking work and also indicates any problem areas in numeracy.
Cindy Silvester is a supply teacher in Greater Manchester.