To review a partial answer, separate what is correct, what is missing and what the question actually asked. Then write the next line yourself. You keep the work you did, and you fix one specific thing.
This applies to any subject where you show working. A half-finished answer is useful evidence, because it tells you exactly where your method runs out.
Why is a whole-answer “wrong” not helpful?
A cross at the end of a question says nothing about which part failed. Often the setup is right, the method is right, and one step is missing. Calling the whole answer wrong throws away good work and hides the real gap.
Reviewing in parts keeps what you earned and points to one task, such as “I forgot to convert units” or “I stopped before the question asked for area”.
How do I review, step by step?
- Reread the question and underline what it asks for in the end.
- Read your working line by line. Tick every line that follows logically from the last.
- Find the last correct line. Everything before it is solid.
- Name what stopped you: a missing idea, a slip, or running out of time.
- Write the next line yourself and finish the answer.
- Check the final answer against the question.
Worked example
Question: the length of a rectangle is 3 cm more than its width. The perimeter is 26 cm. Find the area.
The student’s partial answer:
- Let the width be w. Then the length is w + 3.
- 2(w + w + 3) = 26
- 4w + 6 = 26
- 4w = 20, so w = 5
The student stopped there.
Review. The setup is correct: a perimeter equation with w and w + 3. The algebra is correct: 4w = 20 gives w = 5. The last correct line is w = 5.
What was missing? The question asked for the area, not the width. The length is 5 + 3 = 8 cm. The area is 5 × 8 = 40 cm².
Check: perimeter 2(5 + 8) = 26 ✓.
So the student’s method was sound. The gap was reading the final demand, not solving equations.
What is a common mistake?
The mistake is to treat a partial answer as all or nothing, either copying the full solution without thinking or throwing the attempt away.
Mistaken review: “I got it wrong, let me read the answer: 40. OK.”
Nothing has been learned. The student does not know whether the error was in the algebra, the setup or the final step.
The correction is to write the gap in one sentence: “I solved for width but did not go on to area.” That sentence is something you can watch for in the next question.
Check yourself
Review each partial answer. Say what is correct and what is missing.
1. A train travels 150 km at 60 km/h. How long does it take, in minutes? The student writes: time = 150 ÷ 60 = 2.5.
Show answer
The method is correct, and 2.5 is in hours. The question asks for minutes, so 2.5 × 60 = 150 minutes. The missing step is the unit conversion.
2. Find 15% of 240. The student writes 0.15 × 240 = 3.6.
Show answer
Converting 15% to 0.15 is correct. The multiplication slipped: 0.15 × 240 = 36. A quick check is 10% of 240 = 24 and 5% = 12, so 15% = 36.
3. Solve 2x + 5 = 17. The student writes 2x = 12 and stops.
Show answer
The first line is correct. The last step is dividing by 2: x = 6. Check: 2(6) + 5 = 17.
What should I do next?
Keep a note of the gap sentence from each review. After a few questions, patterns appear, and you can plan them into your realistic revision planner. To decide what to revise first, read choosing realistic tasks when the exam feels close and separating required scope from optional extension.
The students’ guide lists other situations.
Reading your own working with fresh eyes is hard. In the trial hour of online one-to-one Mathematics tuition, a teacher can look at your partial answers and show you which lines earn credit and which step comes next.