Check a worked math solution

A convincing explanation can still contain an arithmetic or sign error. Treat a worked answer as a sequence of claims you can check. Preserve the original question, including units and restrictions, so the review does not accidentally solve a different problem.

Work through it

1. Copy the expression exactly and list any domain restrictions. Compare the copied version with the original before simplifying.
2. Ask for one step at a time and explain why that transformation is valid. Recalculate arithmetic independently rather than accepting a fluent description.
3. Substitute the proposed result into the original equation. For a word problem, check the units, sign and reasonable size of the answer.

Check your result

• The copied problem matches the source.
• Restrictions are still satisfied.
• The final check uses the original equation, not only the last intermediate step.