Basic Mathematics and Data Interpretation
Basic Mathematics and Data Interpretation tests practical arithmetic: percentages, ratios, averages, rates, unit conversions, and reading tables or graphs accurately. The math is not advanced, but the wording and units are where candidates lose points.
Core rules
- Identify the quantity asked for and its unit before calculating.
- Percent change = (new - old) / old x 100. Percent of a number = percent / 100 x number.
- Distance = rate x time; rearrange only after writing the formula.
- A weighted average uses the sizes of the groups, not a simple average of group averages.
- On tables, read the row and column labels, note units, and check whether the axis starts at zero.
Worked example
A patrol car travels 180 miles in 3 hours. Average speed is 180 / 3 = 60 mph. If the next leg is 90 miles at 45 mph, time = 90 / 45 = 2 hours. Total distance is 270 miles and total time is 5 hours, so overall average speed is 270 / 5 = 54 mph-not the average of 60 and 45 (52.5 mph). The weighted calculation matters because the times differ.
Traps that cost marks
Using the wrong denominator in percent change; mixing minutes and hours; averaging percentages without weighting; and choosing an answer that is numerically close but has the wrong unit. In data questions, a graph can show a large visual rise while the absolute change is small, so read the scale.