Translated from the Swedish by Malcolm Reid All real life mathematics is problem solving. You can practise problem solving in different ways. In this book solving problems is practised in a different way from most mathematics books you have seen before: You get no clues to the type of calculation from the title; Some problems may have no solution, whereas others may have many solutions Sometimes you can find a simple solution, but check very carefully to see if it is right. The problems are designed to be a little extra tricky. The contents are divided into 4 categories with the answers at the back: * problems ** problems (a little harder) *** problems (can be quite tricky) The week's problem The week's problems are intended to be solved in groups, pairs or individually at school or maybe at home with the whole family. The other problems are often also best solved in a group. Part B contains harder problems than Part A: but as most problems are language and logic based this is not easy to define. What is easy for one solver can be almost impossible for another, and vice versa. Neither of the parts need advanced mathematical knowledge, but despite this there are problems to which many adults either cannot find a straightforward solution or give the wrong answer (for Part B it is useful if you know what "percent" means).