Number Book is a series of graded activity books designed to help children learn basic calculation skills including addition, subtraction, multiplication and division. Number Book 4 is suitable for children making the transition from Key Stage 1 to Key Stage 2 and includes: multiplication and division by 2 and 3, tens and units, counting in tens number facts (for example pairs of numbers that add up to 20), using a hundred square, recognition of coins to 50p, counting money and giving change, vertical addition and subtraction (without borrowing or carrying).