Mathematics for the WAEC Exam

Common failure modes

These are the patterns that cause most candidates to lose marks on this topic. Recognising them in advance is half the work.

• !Factorization errors in quadratic equations — especially when the leading coefficient is not 1
• !Misapplying circle theorems (confusing angle at centre vs angle at circumference)
• !Not showing working in essay questions — WAEC awards method marks

Study tips

• 1Memorize all WAEC circle theorems with diagrams: angle at centre, angle in semicircle, alternate segment, cyclic quadrilateral.
• 2Show all working for every calculation — WAEC Paper 2 awards marks for method even if the final answer is wrong.
• 3Practice the change-of-subject formula for algebraic fractions — it appears in every WAEC paper.

Sample WAEC Mathematics questions

These sample items mirror the format and difficulty of real WAEC questions. Practice with thousands more on the free Koydo question bank.

1. 1

   Solve: 2x² − 5x − 3 = 0

   • Ax = 3 or x = −1/2Correct
   • Bx = −3 or x = 1/2
   • Cx = 3 or x = 1/2
   • Dx = −3 or x = −1/2
   Why this answer?

   Factorize: 2x² − 5x − 3 = (2x + 1)(x − 3) = 0. Setting each factor to zero: 2x + 1 = 0 gives x = −1/2; x − 3 = 0 gives x = 3.

2. 2

   An angle inscribed in a semicircle is always:

   • A45°
   • B60°
   • C90°Correct
   • D180°
   Why this answer?

   By the angle in a semicircle theorem (Thales' theorem), any angle inscribed in a semicircle (where the diameter is the chord) is always 90°. This is one of the most tested WAEC circle theorems.