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Auralith Learning

Year 7 · Maths · Equality and equivalence · Lesson 1

One-step equations: add and subtract

Solve one-step equations involving addition and subtraction using the balance method and inverse operations, and form simple equations from words.

Whiteboard video lesson: One-step equations: add and subtract

28-minute video lesson

Teaching, worked examples and 20 practice questions solved step by step.

Watch free for a month

What your child will learn

  • Understand what an equation is
  • Use the balance method
  • Solve x + a = b and x − a = b
  • Form equations from words
  • Check solutions

The method

  1. Look at what is being done to x.
  2. Do the inverse operation to both sides.
  3. + undoes −, and − undoes +.
  4. Check by putting your answer back in.

Key words: equation, solve, inverse, balance, solution.

Worked examples

The first three practice questions from the lesson, with every step.

Question 1

Solve x + 3 = 10.

  1. Step 1: Subtract 3 from both sides
  2. Step 2: Write the new equation
  3. Step 3: Check your answer

Answer: x = 7

Question 2

Solve x + 11 = 19.

  1. Step 1: Subtract 11 from both sides
  2. Step 2: Write the new equation
  3. Step 3: Check your answer

Answer: x = 8

Question 3

Solve x − 6 = 5.

  1. Step 1: Add 6 to both sides
  2. Step 2: Write the new equation
  3. Step 3: Check your answer

Answer: x = 11