Measurement, Estimation, and Units
Measurement questions test unit conversion, estimation of realistic magnitudes, and simple geometry of length, area, volume, time, and money. You must know the metric prefixes (kilo = 1000, centi = 1/100, milli = 1/1000) and common conversions (1 km = 1000 m, 1 hour = 60 minutes, 1 kg = 1000 g). For area, conversions square the factor: 1 m² = 10,000 cm². For volume, they cube it.
Estimation questions ask whether a value is plausible: a door is about 2 m tall, a car weighs about 1.5 tonnes, a bath holds roughly 150 litres. Sanity-check by comparing against a familiar reference.
Traps: converting area or volume with a linear factor; forgetting to carry units through a calculation; and confusing perimeter with area. Time arithmetic is a frequent stumbling block - 1.5 hours is 1 hour 30 minutes, not 1 hour 50 minutes.
Worked example: a rectangle is 3 m by 50 cm. Convert to the same unit: 3 m × 0.5 m = 1.5 m². Rule of thumb: convert everything to one unit before multiplying, and check that the answer's unit matches what was asked.