Inverse operations
Objective. Use inverse operations to find missing values and check results.
- 1. Learn
- 2. Worked example
- 3. Practice
- 4. Feedback
- 5. Continue
Learn: the key idea
Inverse operations is built on a small number of dependable facts. Choose efficient operations and reason through multi-step situations. Represent the information first, choose a method deliberately, show each step and use an inverse operation or estimate to check that the result fits the question.
Worked example
Work out 189 ÷ 7.
- 1Identify the mathematical information and what must be found.
- 2Represent it with a number line, diagram, table or expression where helpful.
- 3Apply the relevant fact carefully and keep each line clear.
- 4Check the result against the conditions in the question: 27.
Answer: 27
Concept mastery
Based on your past attempts at this lesson — the question types to practise again come first.
Complete a practice set to see your concept breakdown here.
Practice
Practice happens on its own screen, one question at a time. Answers stay hidden until you submit yours, and you can stop and pick up at the same question later.
Start practisingCommon mistake. A common mistake in inverse operations is to apply a remembered procedure before reading the signs, units or order carefully. Write the structure first, then calculate and check.
Your progress
Tick each step as you finish it. Your exact reading position is saved automatically, so Continue drops you back on the same line.
0 of 5 steps complete
Your place saves automatically as you read.