Primary Math

Must-Know Ratio Concepts for P5 & P6 Math Students

As a parent, you might have noticed that Primary Math Ratio Concepts can often pose a challenge for students in Primary 5 and 6. To alleviate your concerns and provide guidance, we’ve compiled a comprehensive guide on the four most essential ratio concepts your child should master. So, let’s delve into these must-know ratio concepts:

1. One side unchanged or Constant Part

2. Total unchanged or Constant Total

3. Difference unchanged or Constant Difference

4. Everything Changed


You must be familiar with these concepts as they are routinely evaluated in Primary Math exams, including PSLE.


Let’s learn the applications of these important Primary concepts:

1. One side unchanged or Constant Part

2. Total unchanged or Constant Total

This question is more challenging as it consists of 2 concepts in one problem sums.

Concept 1: Total Stays the Same

Concept 2: Repeated Identity

It is important that one is able to recognise that the total number of items for A, B and C stays the same too.

A, B and C are repeated in both ratios, except that they are grouped differently in each ratios.

Watch the 2 videos to find out how these questions are solved.

3. Difference unchanged or Constant Difference

When will the difference stays the same

1) When equal number of items are added

2) When equal number of items are removed

3) Age question when the question is comparing 2 people’s ages.


The age of mother is 60 years old. Her daughter is 35 years old.

The age difference between mother and daughter is 60 – 35 = 25 years.

4. Everything Changed

Watch the video to find out how you can solve the question easily with the use of the Tic – Tac – Toe Table.

Understanding Primary Math Ratio concepts proves essential for your child’s exam success. These fundamental principles serve as the cornerstone for various mathematical problems and frequently feature in assessments.

At BlueTree, our specialized classes are meticulously crafted to equip your child with a profound comprehension of these concepts. This approach ensures their ability to confidently tackle a myriad of math questions, including those related to ratios in their exams. With our expert guidance, comprehensive curriculum, and tailored instruction, your child will acquire the skills and knowledge essential for excelling in Primary/PSLE Math exams, securing top grades, and gaining a competitive edge for a brighter academic future with BlueTree’s P5 & P6 Math classes.

To learn more, please don’t hesitate to reach out to us via WhatsApp by clicking here.

Read Also: Unlocking the Secrets of Equal Concept: Mastering Popular Problem Sums Questions for Primary/ PSLE Math