Look at a supermarket receipt, a football score, or the odometer in a car: every number you meet is built from just ten digits (0–9). The clever part is place value — the same digit is worth a different amount depending on where it sits. The 5 in £5 buys a sandwich; the 5 in £500 buys a laptop. Same digit, very different money.
Reading the columns
Think of the columns as boxes lined up in a row. Starting from the right, each box is worth ten times the one before it — units, then tens, then hundreds, then thousands, and on it goes.
| Thousands | Hundreds | Tens | Units |
|---|---|---|---|
| 4 | 7 | 3 | 2 |
| 4000 | 700 | 30 | 2 |
So 4732 means 4 thousands + 7 hundreds + 3 tens + 2 units, which is 4000 + 700 + 30 + 2.
Decimals — going past the units
What if we need part of one? The decimal point is the fence between whole amounts on the left and parts of one on the right. The columns keep dividing by ten as you cross it:
| Units | • | Tenths | Hundredths | Thousandths |
|---|---|---|---|---|
| 3 | • | 0 | 6 | 0 |
So in 3.06 the 6 is in the hundredths column → six hundredths (0.06). The 0 in the tenths column isn't lazy — it holds the 6 in the right place, just like £3.06 is not the same as £3.60.
Comparing & ordering numbers
To put numbers in order, treat it like judging a race photo — line everything up fairly first, then look for the first place they differ:
- Line the numbers up by their decimal point.
- Compare digits from the left — the first column where they differ decides which is bigger.
- If one decimal is shorter, add zeros on the end to make them the same length (0.4 = 0.40).
Rounding to a nearby number
Rounding means swapping a number for a tidy nearby one. Look at the digit just after the place you are rounding to: 5 or more rounds up, 4 or less stays. So 47,380 to the nearest thousand is 47,000 (the hundreds digit is 3, so round down), while 8,649 to the nearest hundred is 8,600.
The < and > symbols
< means "less than" and > means "greater than". The wide open end always faces the bigger number — picture a hungry mouth that always wants the larger amount: 3 < 8 and 8 > 3.
Memory hook: a digit's value = its face value × its column. To compare, line up the decimal points and read left to right — the greedy mouth points at the bigger number.