REVISION NOTES
IGCSE Edexcel Mathematics A
2.3 Expressions and Formulae
2.3.1 Understand that a letter may represent an unknown number or a variable
2.3.2 Use correct notational conventions for algebraic expressions and formulae
2.3.3 Substitute positive and negative integers, decimals and fractions for words and letters in expressions and formulae
2.3.4 Use formulae from mathematics and other real-life contexts expressed initially in words or diagrammatic form and convert to letters and symbols
2.3.5 Derive a formula or expression
2.3.6 Change the subject of a formula where the subject appears once
A formula usually has a single letter term on the left-hand side of the equals sign. This is called the subject of the formula.
Sometimes you will want to rearrange the formula so that one of the other letters become the subject instead.
2.3.7 Understand the process of manipulating formulae or equations to change the subject, to include cases where the subject may appear twice or a power of the subject occurs (Higher Tier Only)
