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This puzzle is mostly maths, with a little lateral thinking and a lot of memory.

Start with the price tag for the eggs. The alphabet is written round the outside to help count along. E plus one is F, because F is one letter further round clockwise. G plus two is I. G plus fifteen is V. S minus fourteen is E. That means that it spells FIVE at the bottom, and so £5 is the price for 20 eggs.

The price tags for the book and the milk are the same, with the only difference being that the letters are scrambled. However, the arrows and colours show which letter goes where. BOOK becomes NINE and MILK becomes FOUR.

Using the speech bubbles on the right, you can work out that a big cake is £6, a little cake is £3, a bag of apples is £2, and four eggs (as opposed to 20 eggs) is £1.

This means that buying a big cake and a bag of apples costs a total of £8, and so if adding a bag of sweets made it £11 then the sweets must have cost £3.