PSLE Mathematics: Fractions and Ratios Complete Guide

Quick answer

Fractions and ratios can feel overwhelming, especially when you see a PSLE question and your heart sinks. But don't worry, okay? Once you break down the problem into smaller steps, you'll find it much easier to tackle. Let's go through the steps together so you can feel more confident.

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What you need to know

Fractions are parts of a whole. Imagine a pizza. If you cut it into 4 pieces and eat 1, you've eaten $\frac{1}{4}$ of the pizza. Ratios, on the other hand, compare two quantities. Like if there are 2 apples and 3 oranges, the ratio of apples to oranges is 2:3.

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Understanding Fractions

Fractions can be tricky because they need you to see parts of a whole. I often tell my students to think of a chocolate bar. If you share it with a friend, you each get a fraction.

A simple trick I teach my students is to always draw it out. This way, you can see how much each part is and it becomes less confusing.

Step 1: Identify the numerator and the denominator.
Why: The numerator (top number) tells you how many parts you have. The denominator (bottom number) tells you into how many parts the whole is divided.

Step 2: Simplify the fraction if possible.
Why: This makes your fraction easier to work with and is often required in exams.

Understanding Ratios

Ratios are like fractions but show a relationship between two or more items. Think about recipes. If you put 1 cup of rice to 2 cups of water, the ratio is 1:2.

Step 1: Write the ratio in the form a:b.
Why: This is the standard way to express ratios and makes comparisons clearer.

Step 2: Simplify the ratio.
Why: Just like fractions, simplified ratios are easier to understand and use.

Common mistakes students make

Mixing up Numerators and Denominators

Many students make the mistake of swapping numerators and denominators. Parents are often surprised that such a simple mix-up can lead to losing marks. Always check that you have the right numbers in the right places.

Forgetting to Simplify

Not simplifying fractions and ratios is a common slip. In exams, you might lose marks even if your answer is correct but not in its simplest form. Remember to always check if you can simplify.

Misreading the Question

This part trips everyone up. Sometimes, students misread what the question is asking. If you see a question with both fractions and ratios, breathe first and underline key parts.

Exam tip

In your PSLE, presentation is key. Make sure your answers are neat and all steps are shown. This way, even if your final answer is wrong, you might still get marks for the working. Also, don't panic if the question looks long. Break it down into smaller parts and tackle each one step-by-step.

Worked examples

Question 1

A cake is divided into 8 equal slices. John eats 3 slices. What fraction of the cake has he eaten?

Solution

Step 1: Identify the total number of slices.
Why: This gives us the denominator. Here, it's 8.

Step 2: Count the slices John eats.
Why: This is the numerator. Here, it's 3.

Step 3: Write the fraction as $\frac{3}{8}$.
Why: This shows the part of the cake John has eaten.

Question 2

If there are 4 red marbles and 6 blue marbles, what is the ratio of red to blue marbles?

Solution

Step 1: Count the number of red marbles.
Why: This gives us the first number in our ratio, which is 4.

Step 2: Count the number of blue marbles.
Why: This gives us the second number in our ratio, which is 6.

Step 3: Write the ratio as 4:6.
Why: This is the initial comparison between red and blue marbles.

Step 4: Simplify the ratio to 2:3.
Why: Ratios should be in their simplest form for clarity.

Quick check

1. Simplify the fraction $\frac{6}{9}$.
2. What is the ratio of 5 apples to 10 oranges?
3. If a pizza is cut into 12 slices and you eat 4, what fraction of the pizza is left?

Answers:

1. $\frac{2}{3}$
2. 1:2
3. $\frac{8}{12}$ or $\frac{2}{3}$

Quick summary

• Fractions are parts of a whole; simplify them for clarity.
• Ratios compare quantities; always simplify.
• Avoid mixing numerators and denominators.
• Show all steps in exams for partial marks.
• Break down complex problems into smaller steps.

FAQ

Q 1: How do I remember the difference between fractions and ratios?
A: Think of fractions as slices of a cake (parts of a whole), and ratios as the recipe (comparing ingredients).

Q 2: Why do I need to simplify fractions and ratios?
A: Simplifying makes it easier to understand and is often required in exams for full marks.

Q 3: What if I forget to simplify during an exam?
A: If you remember later, go back and simplify. You might still get some marks for the correct working.

Q 4: How can I practise fractions and ratios effectively?
A: Short, daily practice works best. Try using stories or drawings to visualise the problems.

Practise with free question sets

Work through exam-style questions with answers and step-by-step solutions:

• 35+ PSLE Math Heuristics Questions for 2026/2027 (Singapore MOE Syllabus) Every Student Should Know
• [40+ P 5 Math Fractions Questions for 2026/2027 (Singapore MOE Syllabus)](/questions/p 5-fractions-questions)
• [35+ PSLE Ratio Questions for 2026/2027 (Singapore MOE Syllabus) with Step-by-Step Solutions](/questions/p 6-ratio-questions)
• Topic study hub

[Practise unlimited questions on Tutorly.sg/app](https://www.tutorly.sg/app)

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