You may have calculated the remaining money but expressed it backwards.
PRIMARY 4 · MATHEMATICS
Money
Top 5 mistakes
Ranked by how often they appear across 15 MOE-aligned practice questions in our archive.
You may have forgotten to add the book and game costs.
This would be true if his starting amount was different.
Made an arithmetic slip adding $24.30 + $7.60, computing $32.10 instead of $31.90, then subtracted: $50.00 − $32.10 = $17.90.
Added only the book and ruler ($14.50 + $9.80 = $24.30) and subtracted from $50.00, forgetting to include the water bottle: $50.00 − $24.30 = $25.70.
Want to fix these mistakes for your child?
Superholic Lab's quiz engine flags every misconception by name and routes your child to targeted practice in our 3-day Plan Quest. Free 7-day trial.
Start a free 7-day trial →