Many lost marks in Mathematics come from a single word: a student knows the method but answers a slightly different question. This glossary gives each term a plain meaning, a small example, and the word it is most often mixed up with.
Sixteen terms are grouped by topic. Each links to the lesson that teaches it. The English, Malay and Chinese concept bridge shows the same terms in all three languages.
Number and proportion
Integer. A whole number, positive, negative or zero: −3, 0, 12. Example: 2.5 is not an integer. Confused with rational number, which includes every integer and also fractions such as 3/4. See number sense.
Factor and multiple. A factor divides a number exactly; a multiple is what you get by multiplying it. Factors of 12 include 3 and 4; multiples of 12 include 24 and 36. Confused with each other, because both involve the same numbers. See using factors.
Ratio and fraction. A ratio compares parts, 2 : 3. A fraction compares a part to the whole, here 2/5 and 3/5 of the total. Example: a 2 : 3 ratio of red to blue means red is 2/5 of all the beads, not 2/3. See ratio versus fraction of the total.
Percentage change and percentage points. A rise from 40% to 50% is 10 percentage points, but it is a 25% increase in the percentage itself (10 ÷ 40). Confused with each other in news and exam questions. See percentage change versus percentage points.
Base (of a percentage). The quantity that represents 100%. Example: after a 20% rise to RM 120, the base was RM 100, so a 20% fall from RM 120 is not back to RM 100. See why rises and falls do not cancel.
Indices and precision
Standard form. A number written as A × 10ⁿ where 1 ≤ A < 10. Example: 0.00072 = 7.2 × 10⁻⁴. Confused with any number with a power of ten, such as 72 × 10⁻⁵, which is the same value but not standard form. See small measurements in standard form.
Significant figures and decimal places. Decimal places count digits after the point. Significant figures count from the first non-zero digit. Example: 0.004 07 has 5 decimal places but 3 significant figures. See choosing sensible significant figures.
Upper and lower bound. The largest and smallest values a rounded measurement could have come from. Example: 8.4 cm to 1 decimal place lies from 8.35 up to, but not including, 8.45. Confused with error or tolerance, which are different ideas. See recovering an interval.
Accuracy and precision. Precision is how many digits you report. Accuracy is how close you are to the true value. Example: writing 3.141 593 for π is precise; writing 3.2 is less precise but still close. See accuracy versus displayed decimal places.
Algebra and graphs
Expression, equation and formula. An expression such as 3x + 2 has no equals sign. An equation such as 3x + 2 = 11 can be solved for x. A formula such as A = lw links quantities and can be rearranged. See equations and formulas.
Expand and factorise. These are opposites. Expanding turns 3(x + 2) into 3x + 6. Factorising turns 3x + 6 back into 3(x + 2). Confused with simplify, which means write in a shorter equivalent form. See factorising with a common factor.
Gradient and intercept. The gradient is how steeply a line rises; the y-intercept is where it crosses the y-axis. In y = 2x + 5, the gradient is 2 and the intercept is 5. See coordinate geometry.
Geometry, trigonometry, data
Congruent and similar. Congruent shapes are identical in size and shape. Similar shapes have the same shape but may differ in size, so lengths scale by a constant factor. See similarity, congruence and scale.
Bearing. A direction measured clockwise from north, written with three figures, such as 045°. Confused with an ordinary angle on a diagram, which may be measured from any line. See non-right triangles and bearings.
Mean, median and mode. The mean is the total divided by the count; the median is the middle value when sorted; the mode is the most common value. For 2, 3, 3, 4, 13 the mean is 5, the median is 3 and the mode is 3. See statistics and distributions.
Experimental and theoretical probability. Theoretical probability comes from equally likely outcomes, such as 1/6 for a fair die. Experimental probability comes from trials, such as 18 sixes in 90 rolls, which gives 1/5. The two are close only if there are many trials. See probability reasoning.
How to use this glossary
Choose three terms you hesitated on. For each, write your own one-line example, then say aloud why the confusable word does not fit. Return to the terms a week later.
If you are unsure which syllabus terms apply to you, check the notation and content for your code on the Cambridge page, and see the Mathematics learning guide. A teacher in online one-to-one Mathematics tuition can also ask you to explain a term and notice where your meaning and the exam meaning differ.