According to Pei Chun Public School, the questions were not beyond the primary one students' understanding ability.

When questioned by Lianhe Wanbao, the primary school said that the maths problems highlighted by a parent in the previous report were indeed similar to its past exam questions.

The school's Head of Department (HOD) for Mathematics said that the study of mathematics should not only stick to the stipulated curriculum, but should also train a student's inference ability. As such, it was difficult to pinpoint which chapter or section of the curriculum the problems were testing.

"This question (see graphic below) tests simple mathematical reasoning," he told the Chinese Daily.

Although students only learn algebra in primary six, primary one students can also solve the problem if they understand what they have learnt in their daily maths lessons and have a keen mathematical ability, he continued.

Exams are structured neither to bring down a student's confidence nor to allow all students to get a 100 per cent score, said the HOD.

Every school will set questions with different levels of difficulty with the aim of differentiating students of varying abilities, he added.