Function machines can be a good way to help learners form algebraic expressions. This worksheet uses function machines to provide scaffolding for creating algebraic expressions and producing a function machine from an expression. This can then be done nicely by using function machines to rearrange simple formulae.
In section A, learners need to fill in the boxes to build the expressions from the two-step function machines.
Section B does the opposite of section A.
Section C involves a bit more algebraic manipulation with some three-step function machines.