Numerical aptitude · Shapes and data
Data interpretation, made easy
💡 The idea
Data questions are just percentages, averages and ratios on numbers you read from a chart. Read carefully, then do simple maths.
🧭 The method: 3 steps
- Read the question and find exactly which numbers you need (circle them).
- Write those numbers down; ignore the rest.
- Do the maths: total, average, ratio or % change (divide by the EARLIER value).
🎬 Every kind of question, in pictures
Pick a kind. Guess the answer first, then watch the picture work it out. Tap any step to see it in the picture.
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✏️ Worked examples
Example 1. Sales Jan 40, Feb 60. % increase?
- Change = 20
- 20 ÷ 40 (the earlier) = 0.5
- = 50%
Example 2. Pie chart: rent is 90° of $4,000. Rent?
- 90 out of 360 = 1/4
- 1/4 of 4,000 = $1,000
⚠️ Where people go wrong
- Dividing % change by the later value.
- A pie chart in degrees: the whole is 360, not 100.
- Reading the wrong row or column of a table.
📌 Remember
- % change = change ÷ old × 100
- Pie: part/360 or part/100 of the total
- Average = total ÷ how many