Numbers, Ratio & Percentage Mistake Finder
Find the percentage, ratio, proportion, unit, or interpretation mistake costing you marks.
Loading Mistake Finder…
Before you start
What this Mistake Finder checks
Numbers, ratio and percentage questions can look familiar while asking for very different reasoning. The calculation may be short, but deciding what a percentage is taken from, what a ratio represents, or which quantity should be scaled is where many marks are lost. This Mistake Finder checks the method habits behind those decisions.
The aim is to make number work more dependable in O-Level G3 Math contexts: identify the whole before finding a part, connect a ratio to the correct total, and keep units meaningful throughout a rate or proportion problem. It does not disclose the Finder's answers. Instead, it helps show where a recurring setup error may be hiding behind otherwise confident arithmetic.
Common mistake patterns
- Using the wrong percentage base after an increase, decrease, or comparison
- Confusing ratio parts with the total quantity
- Setting up a scale or proportion relationship incorrectly
- Misreading units, rates, or what a result is measuring
How it works
Answer 8 short questions and Mentora marks them automatically. Your score, full breakdown, correct answers, explanations, mistake-pattern diagnosis, repair guidance and topic-specific 7-day repair plan appear immediately.
Because the questions are short, this is a focused starting point rather than a replacement for your full revision. It is most useful when you want evidence for what to practise next, instead of choosing a topic only because it felt difficult in the last paper.
Who it is for
It is for Singapore Secondary students in an O-Level G3 Math context who can complete routine calculations but are unsure why ratio and percentage marks still disappear. Use it before choosing whether to revise percentages, proportion, rates, or interpretation.
What happens after
Rather than treating every wrong answer alike, the result looks at whether mistakes seem isolated, repeated within numbers and proportion, or spread across different methods. That gives you a more useful starting point for revision.
Use that picture to plan a smaller, more specific revision session. A student does not need to treat every topic as equally weak: targeted practice is easier to review, and it gives you a clearer way to check whether the same method mistake has stopped recurring.