Missing units: a correct answer that can still cost marks
Your child's answer is the right number with no unit after it: 81 instead of 81 cm². Many PSLE answer lines print the unit for you, but when the line is blank the unit is part of your child's answer, and leaving it out can cost marks. Writing the wrong unit, such as cm instead of cm², is the same habit.
What it looks like
A square has a perimeter of 36 cm. Find its area.
- Length of one side: 36 ÷ 4 = 9 cm
- Area: 9 cm × 9 cm = 81 cm²
Why 81 is wrong: The working is correct, but the final answer has no unit on a line that does not print one.
Why children do it
- Most practice answers have the unit printed on the line, so your child never has to write it.
- Children see the unit as decoration rather than part of the answer.
- Area and volume units (cm², cm³) are easy to confuse with length units when your child is rushing.
How to fix it at home
- Ask your child to write the unit in every line of working, not only at the end.
- Before writing the answer, have your child check: is the answer line blank, and if so, what unit does the question use?
- Practise the three families: cm for length, cm² for area, cm³ for volume.
- When marking homework together, treat a missing unit as an incomplete answer, the same way the exam can.
Questions parents ask
Does the PSLE really take marks off for missing units?
It can, when the unit is not printed on the answer line and is needed for the answer to be complete. It is not worth the risk when writing it takes a second.
What about the wrong unit, such as cm instead of cm²?
A wrong unit is treated as a wrong answer more often than a missing one, so it matters even more.
Where it shows up
Other careless mistakes
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