IGCSE to IB: the maths gap, and how to close it

Most students arrive in the IB Diploma having done well at IGCSE or MYP — and then hit an unexpected wall in the first maths unit. It is rarely a sign of weak ability. It is the transition itself.

What actually changes

IGCSE and MYP reward accurate procedure: follow the method, get the marks. IB rewards reasoning. The questions are less predictable, the language is denser, and a single problem often combines two or three topics at once.

• Algebra is assumed, not taught. Weak manipulation quietly slows down every later topic.
• Calculus arrives fast in AA, and it depends entirely on confident functions and algebra.
• The Internal Assessment (IA) demands independent mathematical thinking, not recall.
• Command terms ("justify", "deduce", "hence") expect a different kind of answer.

Why the gap compounds

A small gap in algebra or functions in September becomes a large gap by mock exams, because everything new is built on top of it. Predicted grades — which drive university offers — are usually set before a student has time to recover. That is why closing the gap early matters so much more in IB than it did at IGCSE.

How to close it

• Diagnose precisely. Find the exact strands that are shaky before they cause trouble.
• Rebuild foundations first. Algebra and functions before anything new.
• Practise IB-style reasoning, not just procedure — multi-step, command-term questions.
• Start the IA conversation early, so topic choice and depth are not last-minute.

One-on-one work is the fastest route here, because the gap is specific to each student. A generic class re-teaches everything; a personalised plan targets only what this student needs.