Numerical Reasoning
What is tested
Expect percentages and percentage change, ratios and rates, averages, unit conversion, simple algebra, and data interpretation from tables, rosters and graphs. Police-relevant contexts appear often: staffing per shift, call volumes, distance and speed, fines and totals, and proportional scaling ('if four officers process 60 reports, how many will nine process?').
Traps
Distinguish percentage points from per cent: going from 20% to 25% is a rise of five percentage points but a 25% relative increase. A 20% rise followed by a 20% fall does not return to the start. Average speed is total distance over total time, not the average of two speeds. Watch unit mismatches - minutes against hours, metres against kilometres, grams against kilograms - and never round mid-calculation; carry the full figure and round only at the end. Read the column heading twice before using a table.
Rule of thumb
Units first, estimate second, compute third, sanity-check fourth. If your answer is wildly bigger or smaller than your estimate, you have misread something, not discovered a surprise.
Worked example
Eight officers answer 240 calls in six hours. At the same rate, how many calls will ten officers answer in four hours? Step 1: find the per-officer-hour rate. 8 officers × 6 hours = 48 officer-hours, so 240 ÷ 48 = 5 calls per officer-hour. Step 2: apply the new conditions. 10 × 4 = 40 officer-hours; 40 × 5 = 200 calls. Answer: 200.