Glossary

Number – Key Terms & Definitions

Q: How many number terms do I need to know for IGCSE?

This glossary covers 16 key number terms. Focus on understanding definitions and being able to use each term in context during exams.

Q: Are these terms for Core or Extended?

Terms are labelled as Core or Extended. Core students should focus on Core-labelled terms, while Extended students need to know all terms.

Essential number vocabulary for IGCSE Mathematics (0580). Each term includes a clear definition and example to help you understand and remember key concepts.

integer

Core

Whole number positive or negative

Example

-3, 0, 7 are integers

prime

Core

Number with exactly 2 factors

Example

2, 3, 5, 7, 11...

factor

Core

Number that divides exactly

Example

Factors of 12: 1,2,3,4,6,12

multiple

Core

Product of a number and integer

Example

Multiples of 3: 3,6,9,12...

HCF

Core

Highest Common Factor

Example

HCF of 12 and 18 is 6

LCM

Core

Lowest Common Multiple

Example

LCM of 4 and 6 is 12

standard form

Core

$a \times 10^n \text{ where } 1 \leq a < 10$

Example

$3.5 \times 10^4 = 35\,000$

significant figures

Core

Digits that carry meaning

Example

3.456 to 2 s.f. = 3.5

decimal places

Core

Digits after decimal point

Example

3.456 to 2 d.p. = 3.46

upper bound

Extended

Highest possible value within rounding

Example

3.5 rounded to 1dp: UB = 3.55

lower bound

Extended

Lowest possible value within rounding

Example

3.5 rounded to 1dp: LB = 3.45

ratio

Core

Comparison of quantities

Example

2:3 means for every 2 of one, 3 of other

proportion

Core

Two ratios that are equal

Example

$\dfrac{2}{3} = \dfrac{4}{6}$

percentage

Core

Number out of 100

Example

$75\% = \dfrac{75}{100} = \dfrac{3}{4}$

reciprocal

Core

1 divided by the number

Example

$\text{Reciprocal of 5 is } \dfrac{1}{5}$

irrational

Extended

Cannot be written as exact fraction

Example

$\sqrt{2}, \pi are irrational$

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Frequently Asked Questions

How many number terms do I need to know for IGCSE?

This glossary covers 16 key number terms. Focus on understanding definitions and being able to use each term in context during exams.

Are these terms for Core or Extended?

Terms are labelled as Core or Extended. Core students should focus on Core-labelled terms, while Extended students need to know all terms.

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