Algebraic notation conventions

Algebraic notation is a precise written language. Edexcel awards method marks for correct notation even when an answer is wrong, so habits matter.

Multiplication

• Numbers go before letters: 3a, not a3.
• Letters in alphabetical order: 3abc, not 3cba.
• Powers indicate repeated multiplication: a³ = a × a × a.
• The multiplication sign is omitted between a number and a letter, between two letters, and between a letter and a bracket: 3(x + 2), not 3 × (x + 2).
• Multiplying like letters: a × a = a²; a × a × a = a³.

Division

• Algebraic fractions are written as a fraction bar: a/b or (x+1)/(x−2).
• Avoid the obelus ÷ in algebra; mark schemes prefer fraction notation.

Coefficients and constants

In 3x² + 5x − 7:

• 3 is the coefficient of x².
• 5 is the coefficient of x.
• −7 is the constant term.
• x² and x are terms (with their coefficients).

Brackets

• (x + 2)² means (x + 2)(x + 2), not x² + 4.
• Implicit multiplication: 4(x + 1) means 4 × (x + 1) = 4x + 4.

Like and unlike terms

Like terms have the same letter parts to the same powers: 3x² and 5x² are like; 3x² and 5x are not. Only like terms can be added or subtracted.

Edexcel exam tips

• Read the question's notation carefully: "ab" never means "a + b" — it means a × b.
• "Square" means raise to power 2: "the square of x" = x².
• "Square root" — use the symbol √.
• Distinguish 2x² (= 2 × x × x) from (2x)² (= 4x²).
• When asked to "write an expression for", give a single term in algebra (no equals sign needed). When asked to "form an equation", use an equals sign.

Common notational errors that lose marks

1. Writing 3 × x as 3x in mark schemes is fine, but writing x3 is non-standard.
2. Forgetting that a − negative becomes a + positive: 5 − (−3) = 8.
3. Misreading 2x² as (2x)².
4. Writing 1/3x instead of x/3 — ambiguous; clarity matters.