This booklet is aimed at teachers working with learners from about entry level 2 to level 1. We suggest some approaches that we have found effective in enabling learners to work on developing an understanding of number, and of the relationships between operations. These are not new ideas, but rather an attempt to collate some strategies that we have seen used effectively. The ideas can be used with other teachers or alone, in order to plan lessons and to challenge your beliefs about mathematics teaching and learning. The key emphasis here is that learners should be encouraged to develop a ‘relational’ understanding of number rather than simply an ‘instrumental’ understanding (“Relational Understanding and Instrumental Understanding”, Richard Skemp, 1976, in Mathematics Teaching issue 77). That is, an understanding of the properties of and the relationships between numbers and between operations, so that in solving new problems they can draw on this and also on their own everyday life strategies.