Bar Model Approach to PSLE-2019 Questions

“There should be no such thing as boring mathematics”

- Edsger Dijkstra

Bar Model Approach to PSLE-2019 Questions

  Ho Soo Thong       Ho Shuyuan 

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Revised July 2021

 In 2019 PSLE Examination, pupils encountered quite a number of challenging math questions.  Here, we intend to highlight the basic mathematics  in the Holistic Bar Modelling Approach to three questions.  

A holistic bar model enables us to have an overview of the solution and see the challenging level of the question.

 

Question 1

psle-8-2-19

Remark  : The question involves three related “Fraction”situations. There is a complex algebraic relation 3X = 7Y for which we apply the Greatest Common Unit Procedure.

Alternatively, we can use the Euclid’s Line-Segment Approach together with an algebraic symbol U as shown below.

psle-19-4

  

Question 2

psle-14-2-19

Remark :  A challenging Distributive Problem involves the algebraic relation 

Cost = number of units × unit cost

The solution apply Distributive Law for deductive approach. 

 

 Question 3

 psle-17-2-19

Remark : The question is quite challenging to pupils. It involves a sequence of numbers and Algebra for a  Sum-difference situation.