GCSE-ready- Home
- Lessons
- KS3 Mathematics
- Place value, ordering and rounding
Place value, ordering and rounding
🎬 The doodle video for this lesson is coming soon. Subscribe on YouTube to see it first.
Every digit in a number has a value that depends on its place. Get this right and ordering, rounding and multiplying by 10 become easy.
Place value
Each column is worth ten times the column to its right.
In 4 352.17: the 4 is worth 4 thousands, the 1 is worth 1 tenth (0.1) and the 7 is worth 7 hundredths (0.07).
In 4 352.17: the 4 is worth 4 thousands, the 1 is worth 1 tenth (0.1) and the 7 is worth 7 hundredths (0.07).
Ordering numbers
Line up the decimal points and compare digits from the left.
0.6 > 0.59 because 6 tenths beats 5 tenths.
On a number line, numbers get bigger to the right, so −2 > −7.
< means less than, > means greater than, ≤ and ≥ include equal to.
0.6 > 0.59 because 6 tenths beats 5 tenths.
On a number line, numbers get bigger to the right, so −2 > −7.
< means less than, > means greater than, ≤ and ≥ include equal to.
Rounding
Look at the digit after the place you are rounding to. 5 or more: round up. 4 or less: keep the digit.
3 847 to the nearest 100 is 3 800 (the 4 tells you to keep the 8).
12.763 to 1 decimal place is 12.8 (the 6 rounds the 7 up).
3 847 to the nearest 100 is 3 800 (the 4 tells you to keep the 8).
12.763 to 1 decimal place is 12.8 (the 6 rounds the 7 up).
Write 0.5, 0.45, 0.405 and 0.54 in order, smallest first.
- Write them with the same number of decimal places: 0.500, 0.450, 0.405, 0.540
- Compare as whole numbers of thousandths: 405, 450, 500, 540
Answer: 0.405, 0.45, 0.5, 0.54
A digit's value depends on its column. Line up decimal points to compare. To round, look at the next digit: 5 or more rounds up.
The interactive lesson includes the diagrams for this topic.
Check you have got it
Answer 7 quick questions with instant marking. If you get one wrong, GCSE-ready shows you why and gives you another go. It is free, and you do not need an account.