Equations & Formulae — Year 7 Revision Notes
These notes cover the balance method for solving equations, one- and two-step linear equations, and substituting into simple formulae.
The balance method
An equation is balanced: whatever you do to one side you must do to the other. To keep it balanced, use inverse operations to undo what has been done to the unknown.
Key Facts & Formulas
- do the same to both sides
- + undoes −, × undoes ÷
Tips
- Aim to get the letter on its own on one side.
- Show each step of working clearly on its own line.
Solving one- and two-step equations
For a two-step equation such as 3x + 4 = 19, undo the operations in reverse order: subtract 4 from both sides to get 3x = 15, then divide both sides by 3 to get x = 5.
Key Facts & Formulas
- 3x + 4 = 19 → 3x = 15 → x = 5
Tips
- Undo addition or subtraction before multiplication or division.
- Check your answer by substituting it back into the original equation.
Substituting into formulae
A formula links quantities, such as P = 4s for the perimeter of a square. Substitute the given value to find the result: if s = 6, then P = 4 × 6 = 24.
Key Facts & Formulas
- P = 4s
- A = l × w
Tips
- Replace the letter with its value in brackets, then calculate.
- Include the correct units in your final answer where appropriate.
Revision Checklist
- I can keep an equation balanced using inverse operations
- I can solve one-step and two-step linear equations
- I can substitute values into a simple formula
- I can check a solution by substituting it back in
Frequently Asked Questions
Which operation do I undo first?
Undo addition or subtraction first, then multiplication or division — the reverse of the normal order of operations.
Build strong foundations in Equations & Formulae
A free trial class with Teacher Rig helps your Year 7 child master Equations & Formulae now — so IGCSE Maths feels familiar, not frightening, later.
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