ACARA AC9M7A01, Substitute into formulas

Year 7 · Algebra

Use variables to write everyday formulas and substitute values into a formula to find an unknown.

Below are free printable maths worksheets that support AC9M7A01. Print them as PDFs, or generate a fresh one. Every maths answer key is computed in code, so it is never wrong.

Teaching guide

What students learn

Use variables to write everyday formulas and substitute values into a formula to find an unknown.

How to teach it

Build algebra from arithmetic: use a variable to stand for an unknown, write the situation as an expression or equation, then keep both sides balanced when solving and check by substituting the answer back in.

Worked example

3x = 21

Answer: x = 7

Why: Divide both sides by 3: x = 21 ÷ 3 = 7

Generated and checked in code, so it is correct.

Watch out for

Treating the equals sign as 'work it out' rather than 'both sides are equal', dropping negative signs, and not applying an operation to every term.