O-Level E Math & A Math

Annotated Model Solutions

Not just the answer — the reason each line earns its mark.

A worked answer tells you what to write. It does not tell you why the examiner pays for it — and that is the part students are actually marked on. Every solution here is written out the way it should appear in a script, with a note beside each line explaining what that line is worth: the method mark, the accuracy mark, and the trap that quietly costs it.

For students, it is a model of how full working should look. For parents, it is the clearest picture of how these lessons are taught — nothing is waved through as “you just do this”.

Free to read, no sign-up. Every question is written from scratch for this site.

Secondary 3 E Math

Trigonometry

Cosine rule, sine rule and area of a non-right-angled triangle

A fully annotated O-Level E Math model solution: solving a non-right-angled triangle with the cosine rule, the sine rule and the ½ab sin C area formula — with the reason each line earns its mark.

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Secondary 3 A Math

Quadratic Functions

Discriminant: the range of k for two distinct real roots

A fully annotated O-Level A Math model solution: using the discriminant to find the range of values of k for which x² + (k + 2)x + (2k + 1) = 0 has two distinct real roots — with the reason each line earns its mark.

Read the annotated solution →

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