Parts & Wholes
The relationship between a part and its whole. Foundation of all percentage calculations.
Practice This ConceptUnderstanding Parts & Wholes
Every percentage question is about parts and wholes. Research is the PART, total budget is the WHOLE. The critical skill is identifying which is which — EPSO places distractors that swap them.
Formula
$percentage = \frac{part}{whole} \times 100$
Key Rules
- Part is always smaller than or equal to whole
- Part / whole gives 0 to 1 (before x 100)
- If answer > 100%, check if you swapped part and whole
- Whole may need to be calculated by summing all parts
Examples in Action
1
18.7 / 140.6
=
13.3%
Research as % of total EU budget
2
140.6 / 18.7
=
7.52 (WRONG)
Swapped — not a percentage
3
54.8 + 53.9 + 18.7 + 13.2
=
140.6
Computing the whole from parts
Common Errors
- Dividing whole by part instead of part by whole
- Using part / (whole - part) instead of part / whole
- Not computing total when not given in table
Pro Tip
Before calculating, write: PART = ?, WHOLE = ?. The part is the smaller specific thing. The whole is the larger total.