KS4 / GCSE · Mathematics — Higher

Functions

What is it

Higher tier functions cover evaluating, composing (combining two functions) and finding the inverse of functions, using formal notation like f(x), fg(x), and f⁻¹(x).

Why it matters

Function notation at GCSE is direct preparation for A-Level, where composite and inverse functions appear constantly — students who master the notation here find A-Level functions dramatically less daunting.

Exam tip

For composite functions like fg(x), always apply the function closest to x first (g, then f) — applying them in the wrong order is the single most common composite function mistake.

Related topics

Want help mastering Functions?

Tell us about the student's goals and confidence — we'll design a personalised plan.