Who writes it
Keith Spencer has taught mathematics for thirty years across US, UK and IB curricula. He holds a B.A. in Mathematics from the University of North Carolina Wilmington and has been licensed to teach in North Carolina, Maryland and Connecticut. KS Maths is his own work and is independent of any school or exam board.
How every number is checked
A worked answer that is wrong is worse than none, so nothing ships on trust. Before any page is published, scripts recompute every number in it and fail the publish if the page disagrees.
At the last full check of the site, on 20 October 2026, 40 separate checks ran across every page, including 314,638 recomputed answers in 73 verifier files. Every one passed: a single failure stops anything being published.
- Every answer checker is run: the right answer is accepted, a near miss is rejected, and every hint can be reached.
- Every figure is executed and must stay inside its frame.
- Every paper and calculator label must agree with the course it is written for.
Error log
When something is found wrong, it is fixed and listed here. Errors reported and fixed: 2, latest 18 October 2026.
- The binomial teacher page carried a calculator note copied from another lesson (eigenvalues, differential equations). Removed, and 38 teacher pages had their calculator notes rewritten for their own topic; a check now blocks a calculator note that names a topic the lesson does not teach.
- Eleven Diploma lessons shared by both courses labelled a calculator question "Paper 1 style", which is wrong for Analysis and Approaches. All now read "Paper 2 style", and a check stops the mistake returning.
Found something wrong? Email hello@ksmaths.com with the page and the question.
KS Maths is run by Keith Spencer, trading as KS Maths, Bangkok, Thailand. hello@ksmaths.com