Primary 4 introduces decimals up to 3 decimal places: notation and place values, comparing and ordering, expressing decimals as fractions and fractions as decimals where the denominator is a factor of 10 or 100, and rounding.
What decimals actually asks of a Primary 4 student
Place value now extends to the right of the point, and the pattern reverses direction: tenths, hundredths, thousandths, each ten times smaller than the last.
The recurring difficulty is that longer no longer means larger. 0.7 is greater than 0.65, which contradicts everything whole-number experience suggests.
Children have in fact been using decimal notation since Primary 2 money. Making that connection explicit helps a great deal.
What the syllabus covers
Under the MOE primary mathematics syllabus, decimals at Primary 4 covers:
- notation, representations and place values
- comparing and ordering decimals
- expressing decimals as fractions
- expressing fractions as decimals when the denominator is a factor of 10 or 100
- rounding decimals to the nearest whole number, 1 decimal place and 2 decimal places
Where the marks actually go
Comparing by digit count, so 0.65 is judged larger than 0.7.
Place-value confusion between tenths and hundredths, particularly when converting to fractions.
Rounding to the wrong number of decimal places, or rounding correctly and then writing the wrong number of digits.
How to practise this properly
Compare decimals by writing them with the same number of decimal places first. 0.7 becomes 0.70, and the comparison with 0.65 becomes obvious.
Tie every decimal back to money where possible. 0.25 as twenty-five cents makes the value concrete.
Name the place value of each digit aloud when converting to a fraction. The name gives the denominator directly.
Round the same decimal to different accuracies in one exercise so the child sees the instruction, not the number, decides the answer.
What this leads to
The rest of Primary 4 uses decimals in all four operations, and Primary 5 extends to multiplying and dividing by 10, 100 and 1000 and to percentage.
This is the case for continuity. When the same curriculum carries a child from Primary 1 to Primary 6, nobody has to reconstruct where an earlier gap was left, and no year is taught as though the previous one did not happen. It also means a child moving up does not have to adjust to a different way of explaining the same ideas.
What lessons at Odyssey are actually like
Our students describe the teaching in their own words. This one is a secondary student — the approach is the same one your child would meet in a primary class, taught at the right level. More are on Odyssey Math TV.
Getting help with this topic
We teach Primary 4 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.
We would rather place a child correctly than quickly. The free trial lesson tells us — and tells you — what is genuinely needed, which is sometimes less than parents expect and occasionally rather more. Book a free trial 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
How many decimal places at Primary 4?
Up to three for notation and place value; addition and subtraction work to two decimal places.
Why does my child think 0.65 is bigger than 0.7?
Because it has more digits. Writing both with the same number of decimal places removes the illusion immediately.
Which fractions convert to decimals at this level?
Those whose denominator is a factor of 10 or 100 — halves, quarters, fifths, tenths and so on.
Is money a good way to teach decimals?
It is the most useful anchor available, since children already handle two decimal places confidently in that context.
