Rearranging Formulae

Make a chosen letter the subject by applying inverse operations while keeping both sides balanced.

Curriculum rangeYears 8–11

Make $w$ the subject of $P = 2l + 2w$ . Whatever you do to one side, do to the other -- working backwards through the order of operations.

Start: $P = 2l + 2w$

Subtract $2l$ from both sides: $P - 2l = 2w$

Divide both sides by 2: $w = \dfrac{P - 2l}{2}$