By the time they do their Year 6 tests, children should have absorbed an abundance of mathematical terminology. More than 600 words are present in the Oxford Primary Maths Dictionary (pound;6.99). Every definition is matched with an example. These sometimes take the form of colour pictures, especially helpful in displaying four kinds of pyramid or the similarity and difference between concentric circles and concentric squares. Diagrams clarify such concepts as the relationship between divisor, dividend and quotient, or how cancelling makes an equivalent fraction.