Fun with Mathematics: Question 3

Test your children’s problem-solving skills – and your own – with this new weekly series of maths questions.

The questions are targeted at Primary 5 students, and the worked solutions and advice have been contributed by Assistant Professor Dr Lee Ngan Hoe, Assistant Head (Mathematics Education – Teaching) of the Mathematics & Mathematics Education Academic Group from the National Institute of Education (NIE) at Nanyang Technological University (NTU). Dr Lee is also the co-author of Shaping Maths and Maths Works!


1. Try to understand the problem first. What is the problem about? What information is given to you and how does it help you to better make sense of the given diagram? What else do you know given that the area of Triangle BEC is three times the area of Triangle AED? Did you use any other information that is not given in the question? If yes, why do you think the information is true for this question?

2. Work out a plan to solve the problem. What can you do with the information given? What other information can you derive? Can you represent all these on another diagram?

3. Try to make sense of the answer. Is there a way to check it? What have you learnt from solving this problem? 


1. Refrain from telling the child what to do, such as telling the child to “look at” the diagram. Instead prompt the child to make sense of the given problem more holistically, e.g. “Did you manage to get all the information about the problem?” or “Where else in the problem can you get more information about the problem?”


2. Encourage the child to annotate the given diagram and to draw additional diagrams where necessary to develop a plan to solve the problem. This would make it easier for the child to better visualise possible relationships that might exist between the unfamiliar.

3. Help the child look for words to activate the necessary mathematics knowledge and skills. In this case, the skill needed is how to find the area of a triangle, which is determined by the formula ½ x base x height. There are several triangles in this problem. Encourage the child to determine the areas of those which they can identify a base and corresponding height as a start.

4. In most problems where diagrams are involved, they are only drawn to proportion but not to scale. Some children may make invalid conclusions about the diagram based on visual illusion.

Brought to you by Marshall Cavendish Education