To round to the nearest 100, find the two hundreds the number sits between. 642 is between 600 and 700.
This time look at the tens digit. If it is 5 or more, round up. If it is 4 or less, round down. 642 has 4 tens, so it rounds down to 600. 851 has 5 tens, so it rounds up to 900. Rounding helps us estimate answers quickly.
Worked example
Round 472 to the nearest 100.
- 472 is between 400 and 500.
- The tens digit is 7, so round up.
Answer:500
Key words
- nearest hundred
- the closest multiple of 100
- estimate
- a sensible guess using rounded numbers
- tens digit
- the digit that decides rounding to 100
Practise this
New questions every time.
Common Core-referenced: 3.NBT.A.1