10 more
245 becomes 255 when we add 10.
2 hundreds, 4 tens, 5 ones
5 tens now
Only the tens digit changes here.
Year 3
Find 10 or 100 more or less than a given number
Use place value to work out 10 or 100 more or less without recounting.
Lesson overview
Number - number and place value
Adding or subtracting 10 changes the tens digit. Adding or subtracting 100 changes the hundreds digit. The other digits usually stay the same unless the number crosses a place-value boundary.
100 less
382 becomes 282 when we subtract 100.
The hundreds digit is 1 less.
10 less
530 becomes 520 when we subtract 10.
The tens digit changes from 3 tens to 2 tens.
Worked example
Find 100 more than 467.
4 hundreds, 6 tens, 7 ones
5 hundreds, 6 tens, 7 ones
- Look at the hundreds digit first.
- Adding 100 means adding one more hundred.
- 4 hundreds become 5 hundreds.
- So 100 more than 467 is 567.
Try it
Decide whether the tens digit or hundreds digit is changing before answering.
Question 1
What is 10 more than 321?
Question 2
What is 100 more than 408?
Question 3
What is 10 less than 670?
Question 4
What is 100 less than 912?
Question 5
Which number is 10 more than 599?
Common mistakes
Watch for these when working through the lesson.
- Changing the ones digit instead of the tens or hundreds digit.
- Adding 10 when the question asks for 100.
- Recounting in ones instead of using place value.
Related topics
These ideas fit closely with this lesson.
- Recognise the place value of each digit in a three-digit number.
- Compare and order numbers up to 1000.