Stage 6 · Big numbers & speed
Large numbers and rounding
Look one place right: 5 or more rounds up.
How to do it
Method
Look one place right: 5 or more rounds up
18653, nearest 1000: 6 ≥ 5, 18000 + 1000 = 19000
Another way
Place-value chart
Thousands 8, hundreds 6 ≥ 5 → 19000
In full
Read a large number in groups of four places from the right: ones, tens, hundreds, thousands, then ten thousands, hundred thousands, millions, ten millions. A digit stands for its place: in 52847 the 2 is in the thousands place and stands for 2000. Building a number from its places, a place with nothing takes a 0: 4 ten thousands 6 tens = 40060. 1000 more than 39600: the thousands digit goes up 1, and ten thousands carry → 40600. Rounding: to round to a place, look at the place just to its right; 5 or more rounds up, 4 or less rounds down, and the places after become 0. 18653 to the nearest thousand: the hundreds digit is 6, 6 ≥ 5, so up, 18000 + 1000 = 19000; 18453 rounds down to 18000. Rounding up can carry on: 49960 to the nearest hundred, the tens digit 6 rounds up → 50000. Another way is to read and write large numbers on a place-value chart and round the same way; the answer is the same.
Worked examples
Have a go first, then open each one for the answer and the working.
Example 1
In 456177, the 6 stands for ?
Show the answer and working
Answer: In 456177, the 6 stands for 6000
In 456177, the 6 is in the thousands place, so it stands for 6 thousands: 6 × 1000 = 6000
Example 2
The ten thousands digit of 14003 = ?
Show the answer and working
Answer: The ten thousands digit of 14003 = 1
14003: from the ones, ones 3, tens 0, hundreds 0, thousands 4, ten thousands 1, so the ten thousands digit is 1
Example 3
8699 to the nearest ten ≈ ?
Show the answer and working
Answer: 8699 to the nearest ten ≈ 8700
8699 to the nearest ten: the ones digit is 9, 5 or more, so round up: 8699 − 9 = 8690, 8690 + 10 = 8700
Example 4
4 hundred thousands 3 ten thousands 1 thousand 6 hundreds 1 one = ?
Show the answer and working
Answer: 4 hundred thousands 3 ten thousands 1 thousand 6 hundreds 1 one = 431601
4 hundred thousands 3 ten thousands 1 thousand 6 hundreds 1 one: 4 hundred thousands → 400000, 3 ten thousands → 30000, 1 thousand → 1000, 6 hundreds → 600, 1 one → 1; the tens hold 0; 400000 + 30000 = 430000, 430000 + 1000 = 431000, 431000 + 600 = 431600, 431600 + 1 = 431601
Practise large numbers and rounding in the game →Stage 6 · Big numbers & speed · Free to start, unlimited questions, no download