Maths practice

Maths practice that starts with your child's mistakes.

Maths mistake practice for NSW Selective and OC preparation starts with one question your child found difficult. Review the method, practise a related problem and return to the idea later.

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What MistakeBook offers

MistakeBook helps families review supported maths questions, including fractions, geometry and word problems. Upload a complete question to get an explanation and, when available, a short set of checked practice questions.

Find the step that needs attention

Ask your child to explain their working before showing the answer. The same incorrect answer can come from a calculation slip, misreading the question or misunderstanding a concept. Use the explanation to guide a conversation; an uploaded answer alone cannot establish why a mistake happened.

Try the idea in a different question

For supported skills, MistakeBook provides related practice when its answer and structure checks pass. Changing the numbers or context helps you see whether your child can use the method again. Some uploads receive an explanation only when suitable practice is unavailable.

Return after a break

Use saved questions and review recommendations to revisit a skill. Look at first answers to different questions across several days, rather than treating one corrected answer as lasting understanding. Parents can follow the practice record by skill.

Original MistakeBook example · No login needed

A fraction of a quantity

A box contains 24 apples. Three eighths are green. How many apples are green? A child answers 3.

Divide 24 by 8. One eighth of the box is 3 apples.
Multiply that one part by 3. Three eighths is 3 × 3 = 9 apples.
Ask: does your answer represent one part or three parts? This helps locate the unfinished step.

Answer: 9 green apples. The answer 3 may indicate that the child found one eighth and stopped; ask about their working to check.

Try another: a box has 32 apples and three eighths are green. Answer: 12. Later, ask your child to explain why both division and multiplication are needed.

Questions parents ask

Is this a complete Selective or OC maths course?

No. MistakeBook supports focused review and practice around individual questions. Use it alongside broader preparation and the NSW Department of Education's official practice resources.

Can I upload a question with a diagram?

Include the complete question, options and a clear diagram. Support depends on the question. Related practice may use a self-contained text problem testing the same idea rather than generate a new diagram.

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Thinking Skills

MistakeBook currently offers checked practice for selected Thinking Skills areas: argument flaws, synonyms, and main idea and conclusion. Hidden assumptions have analysis and explanation only. Spatial rotation, folding and complex image matrices are not supported.

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Selective writing

Writing Studio offers six introductory lessons, draft writing or import, and AI learning feedback. It uses general writing methods in the context of public NSW Selective requirements. It does not provide official exam marks or predict placement outcomes.

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Official exam information

Check the NSW Department of Education for current test information and official practice resources. MistakeBook is an independent learning tool and is not affiliated with the Department.

Start with your child's maths question

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