What this task asks
In error analysis, you are not just solving the problem—you are finding where a student’s arithmetic went wrong and then correcting it. The key is to compare each step with the rules of arithmetic and identify the first incorrect move.
A reliable method
- Read the student’s work carefully. Recompute each step yourself.
- Check one operation at a time. Look for mistakes in addition, subtraction, multiplication, division, signs, or order of operations.
- Find the first error. Later steps may also be wrong, but the first mistake is the important one to name.
- Correct the step. Replace the incorrect result with the right one and continue from there if needed.
- Simplify the final answer. Make sure the corrected result is in simplest form.
Good checks
- Recalculate mentally or with scratch work.
- For subtraction and division, verify by using the inverse operation when possible.
- If negatives appear, check sign rules carefully.
- If there are multiple operations, follow the correct order.
Final check
Your answer should clearly show the error and the corrected conclusion. If the final result can be checked by undoing the operation or substituting back, do that to confirm it is consistent.