Changing the subject · Grade 8

In Grade 8 you learn: changing the subject of a formula.

Changing the subject means rearranging a formula so that a different letter is on its own. If you know A = πr² but want the radius from an area, you rearrange it to r = √(A/π). The moves are exactly the same as solving an equation.

Key facts

• The subject is the letter on its own on one side: in v = u + at, v is the subject.

Other years

• Changing the subject · Grade 9
• Changing the subject · Grade 10