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Dividing Fractions: A Primary 6 Guide

Primary 6 covers dividing a proper fraction by a whole number, and dividing a whole number or proper fraction by a proper fraction, without a calculator.

What dividing fractions actually asks of a Primary 6 student

Dividing by a fraction produces a larger answer, which is the most counter-intuitive result in primary mathematics. How many quarters are in 3? Twelve.

Phrased as “how many of these fit into that”, the result stops being surprising. Phrased as “invert and multiply”, it stays a rule to be trusted and forgotten.

Both readings are needed: the meaning to understand it, the procedure to do it quickly.

What the syllabus covers

Under the MOE primary mathematics syllabus, dividing fractions at Primary 6 covers:

  • dividing a proper fraction by a whole number without calculator
  • dividing a whole number or proper fraction by a proper fraction without calculator

Where the marks actually go

Inverting the wrong fraction. It is the divisor — the one after the division sign — that gets flipped.

Dividing by a whole number by multiplying the numerator instead of the denominator.

Answers not simplified, or improper answers left unconverted where a mixed number was expected.

How to practise this properly

Ask “how many fit into” before calculating. It gives the child an expectation of the size of the answer, which catches inversion errors immediately.

Say which fraction is being flipped and why, every time, until the divisor is identified automatically.

Check the answer against the expectation: dividing by a fraction smaller than one must give a larger result.

Draw one or two examples on a number line. Seeing twelve quarters inside three settles the idea permanently.

Contrast dividing by a fraction with dividing by a whole number in the same exercise. Half divided by 3 and half divided by 1/3 give very different answers, and meeting them side by side prevents the two procedures from blurring together under exam pressure.

What this leads to

Secondary algebraic fractions use the same rule with letters in place of numbers, and rearranging formulae depends on it.

This is why we teach the primary years as one arc rather than six separate ones. Our MOE-aligned curriculum runs from Primary 1 to Primary 6, so when something goes wrong we can trace it to the year it actually formed and repair it there, instead of drilling the level where it happens to be showing up. That distinction usually decides whether extra work produces improvement or simply produces more work.

What lessons at Odyssey are actually like

A student on how the lessons work in practice. The clip is from our secondary classes, but the way concepts are explained is the same at every level. More are on Odyssey Math TV.

Getting help with this topic

We teach Primary 6 maths in small classes at Hexacube, 160 Changi Road #01-02, about three minutes from Eunos MRT. You can see our class schedules and fees, read about our math tutors, or look through the primary school math tuition programme as a whole. If your child is in a nearby school, our primary school directory may be useful too.

The first lesson is a free trial, and it is a diagnosis rather than a sales pitch: we would rather tell you what is actually wrong than sign you up. If the answer is that your child does not need tuition yet, we will say so. Book a free trial class or WhatsApp +65 8512 6882.

What we describe here comes from teaching this syllabus in our own classes since 2012. It is not a forecast for any individual child: progress is produced jointly, by a student willing to do the work with support at home. We do not promise grades. Topics follow the MOE primary mathematics syllabus — check the current syllabus on the MOE website for the definitive version, and see our curriculum page for how we teach it.

Frequently asked questions

Which fraction gets inverted?

The divisor — the fraction you are dividing by.

Why does dividing make the answer bigger?

Because you are asking how many small pieces fit into a larger quantity. Twelve quarters fit into three.

How do you divide a fraction by a whole number?

Multiply the denominator by that number. Half divided by three is a sixth.

Is a calculator allowed?

No, the syllabus specifies these divisions without a calculator.

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