Quantitative Reasoning: Method Before Calculator
What is tested
Quantitative Reasoning is GCSE-level maths applied to tables, charts and short scenarios: percentages, ratios, rates, averages, unit conversion, area and volume, and simple algebra. You have an on-screen calculator and rough paper; speed comes from deciding which operation is needed before you touch the calculator.
Concepts
- Percentage change = (new − old) ÷ old × 100; distinguish this from percentage points.
- Ratio and proportion: scale by finding the multiplier.
- Rates: speed = distance ÷ time. Average speed across two legs is total distance ÷ total time, not the mean of the two speeds.
- Averages and weighted means.
- Conversions: minutes to hours, and squared units (1 m² = 10,000 cm²).
Traps
Unit mismatches are the biggest source of error: grams versus kilograms, per month versus per year, thousands buried in a table heading. Others are reading the wrong row, column or year; rounding too early and losing precision; and answering a different question from the one asked (total vs difference). Distractors are often the result of one common slip, so if your answer appears as an option, check the units before trusting it.
Worked example
A car travels 120 km at 60 km/h, then 120 km at 40 km/h. Time = 2 + 3 = 5 hours; distance = 240 km; average speed = 48 km/h - not 50 km/h.
Rule of thumb: estimate to one significant figure before calculating. If the computed answer is far from your estimate, you have misread the table.