Sibford’s senior teenagers may rightly feel that they have been ignored by the Scene when it comes to competitions – so here is a puzzle for ANYONE who is not yet twenty.

The following sums were prepared on a computer which has the unfortunate fault of introducing an error of +1 or -1 into every figure it prints, ie every figure is one more or one less than the correct figure. Can you find the correct ones?

Please send your answers to the Editor by 16 May and include your name, age, address & school (if appropriate). A small prize will be awarded – if necessary, taking account of neatness (of the submission not the submitter).

An EXTRA PRIZE will be given for a computer programme to solve such puzzles.

D G Tell

[With many thanks to Adrian Lamb]