Primary 4 · Mathematics
P4 numbers to 100 000
One idea carries this whole topic: a digit is not the same as its value. Here is what that looks like in a real number, and how to check your child has it.
- Level
- P4
- Usually taught
- Term 1
- Covers
- 1 concept
What changes at P4
In Primary 4, numbers grow to 100,000, and your child reads, writes, compares and orders them. The idea that makes all of that work is place value: where a digit sits decides how much it is worth.
The catch is telling a digit apart from its value. The 5 in 52,341 is the digit 5, but its value is 50,000, because it sits in the ten-thousands place. Same symbol, ten times more for every place you move it left.
The sentence that costs the mark
What is the value of the digit 5 in 52,341?
What the working usually does
readsthe digit=5
Reads the symbol on the page. It really is a 5, so this looks like a complete answer. It answers the wrong question.
What the question asked
readsthe place=50,000
Reads where the 5 sits, the ten-thousands place, and gives its value there: 5 times 10,000.
The digit really is a 5, so "5" is a truthful reading of the symbol, which is why nothing looks careless. But the question asks the digit's VALUE, and that depends on its place: in the ten-thousands column, a 5 is worth 50,000.
| Ten thousands | Thousands | Hundreds | Tens | Ones |
|---|---|---|---|---|
| 5 | 2 | 3 | 4 | 1 |
The same question, worked properly
Put it in a place-value chart
one digit under each placeWrite 52,341 with one digit under each place, ten-thousands to ones. The 5 lands in the ten-thousands column.
Read the place, not just the digit
the 5 is in the ten-thousandsThis is the step that fails. The digit is 5, but the question asks its VALUE, which depends on where it sits. Answering "5" reads the digit and stops, and that is where the mark goes.
Value = digit × place
5 × 10,000 = 50,000A 5 in the ten-thousands place is worth 5 × 10,000 = 50,000. The same digit 5 in the ones place would be worth just 5. The place is everything.
How can you tell it has clicked?
Point at any digit in a big number and ask "what is this worth here?" If they name the place and give the value (ten-thousands, so 50,000), they have it. If they just say the digit, that is the gap.
Then move the same digit one place to the left and ask again. If they know it is now worth ten times more, place value has clicked.
One thing to try tonight
Write a five-digit number, a flat number with a zero or a price, and point at one digit: "what is this worth here?" Slide the same digit one place along and ask again. It is worth ten times more with each step to the left.
Watch the zeros. In 50,041 the middle zeros are holding places open. Drop one and the whole number changes, which is exactly why place value is worth getting right.
What your child will meet in this topic
- 5-Digit Place Value
Most Singapore schools introduce this in Term 1, though schools do differ by a term either way. If your child’s school runs a different order, you can set it in the schedule on your dashboard.
What it leads to
Place value is the floor everything stands on: adding and subtracting with regrouping, rounding, decimals in P5, and reading any large number in a word problem. A wobble here shows up everywhere later.
A child who reads a digit's value by its place tends to line numbers up correctly when the sums get long, which is where careless place-value slips usually cost the marks.
The same topic in other years
It comes back each year and gets harder, so it helps to see what came before and what is coming.
More in Primary 4
Other topics in the same year, so you can see what sits either side of this one.
Struggling with the working rather than the topic itself? How to help your child with problem sums
See how your child is doing on this topic
StudyLah marks each step separately, so you can see whether it was the setup or the arithmetic that cost the mark.