Quantitative Reasoning rarely needs hard maths — it needs fast, accurate arithmetic and careful reading of tables and charts. The calculator is available, but reaching for it on every step is slower than a trained mental-maths toolkit.
The method
Read the data before the question
Spend a few seconds understanding the units, axes and totals of the table or chart. Most errors are misreads, not miscalculations.
The percentage ladder
Build any percentage from 10%, 5%, 1% and 25%. Need 35%? That's 25% + 10%. Need 3%? That's 1% × 3. It's faster and less error-prone than the calculator for round figures.
Percentage change
Always change ÷ original, not change ÷ new. A rise from 120 to 150 is 30 ÷ 120 = 25%, not 30%.
Sequential percentages
Apply changes one after another, not by adding them. A 10% rise then a 10% fall is not back to the start — it's ×1.1 then ×0.9 = 0.99 of the original.
Ratios and rates
Find the value of one 'part' or one 'unit of time' first, then scale. Keep units written down so you don't multiply when you should divide.
Calculator discipline
Use it for ugly division and multi-digit multiplication; do the round stuff in your head. Keep one hand on the keypad and estimate first so you catch a fat-finger answer.
Quick wins
Estimate before you compute — if the option list has a value miles from your estimate, you've misread the data.
Beware unit traps: thousands vs millions, per month vs per year, % vs percentage points.
Flag long table questions early; a 90-second question is two others you didn't reach.
Now drill Quantitative Reasoning
Practice Quantitative Reasoning free in the real exam interface — the method only sticks when you use it.