In this lesson pupils use decomposition to multiply two numbers together e.g 11 x 12 as (10 + 1)(10 + 2). This process is shown via a Dienes block representation and a grid representation. Pupils then apply exactly the same process to multiplying two numbers together where part of those numbers is unknown e.g (x + 1)(x + 2). This process is shown via an Algebra tile representation and a grid representation. Applying the exact same process, first to examples containing numbers and then to examples containing unkowns, will hopefully encourage pupils to see Algebra as the generalisation of number. Careful variation of questions has been used to draw attention to important aspects of the process and to encourage conjecture.