10 or 100 more or less: what children learn
Year 3 pupils learn to find 10 or 100 more or less than a given number, working with numbers up to 1,000. Adding or subtracting 10 changes the tens digit; adding or subtracting 100 changes the hundreds digit.
Most questions are straightforward, such as 100 more than 456 = 556. The interesting ones cross a boundary: 10 more than 395 is 405, because the tens digit goes from 9 to 0 and the hundreds go up by one. The game deliberately includes many of these, and the wrong answers include the most common slips, such as changing the wrong digit.
This topic covers the Year 3 statutory requirement in the National Curriculum in England (Number – number and place value): pupils should be taught to “find 10 or 100 more or less than a given number”. Year 3 pupils are usually aged 7–8.
For families following US standards, the closest Common Core standard is 2.NBT.B.8, which is taught in Grade 2.
How to play
Answer 10 questions before the clock runs out. Tap an answer, or press 1 to 4. Each game has 10 multiple-choice questions and a 120-second timer. A wrong answer shows the correct one before moving on. You earn up to three stars depending on your score.
Step by step
- Decide which digit changes. 10 more or less changes the tens. 100 more or less changes the hundreds. The ones never change.
- Change that digit by one. 10 more than 263: the tens digit 6 becomes 7, giving 273.
- Watch for crossing a hundred. 10 more than 395: the tens digit 9 cannot become 10, so it becomes 0 and the hundreds go up by one. The answer is 405.
- Check by counting on. Count in tens from the number: 395, 405. If that sounds odd, count 395, 400, 405.
Worked examples
Example 1: What is 100 less than 718?
Working: The hundreds digit 7 becomes 6.
Answer: 618
Example 2: What is 10 less than 304?
Working: There are 0 tens, so we take one hundred and make it ten tens: 304 − 10 = 294.
Answer: 294
Example 3: What is 10 more than 992?
Working: The tens go from 9 to 0 and the hundreds from 9 to 10, giving 1,002. (The game keeps answers below 1,000, but this is a good challenge.)
Answer: 1,002
Common mistakes and how to fix them
- Changing the hundreds when asked for 10 more. Say the question aloud and point to the tens digit before answering.
- Writing 10 more than 395 as 3,105. Use place value counters: ten tens make one hundred, so exchange them.
- Getting 10 less than 304 wrong because there are no tens. Count back in tens: 304, 294. Or think of 304 as 29 tens and 4 ones.
Activities to try at home
- Use money: how much is 10p more than £3.95?
- Play 'up and down the stairs': each step is 10 more; each floor is 100 more.
- Ask for 10 or 100 more than door numbers, page numbers or scores.
Ideas for the classroom
- Use a 1 to 1,000 grid or a number line marked in tens.
- Play a chain game: each pupil adds 10 or 100 and passes it on.
- Use place value counters on a chart to show exchanging ten tens for a hundred.
Printable worksheet
The printable worksheet uses the same question generator as the game, so it practises exactly the same skills. It comes with a separate answer sheet on the second page. Print it, or save it as a PDF from your browser's print menu.
Frequently asked questions
Which year learns 10 or 100 more or less?
It is a Year 3 statutory requirement in the National Curriculum in England. Year 4 extends it to 1,000 more or less.
Why are there so many questions like 10 more than 395?
Because crossing a hundred is where mistakes happen, so it gives the most useful practice.
What is the US equivalent?
The closest Common Core standard is 2.NBT.B.8 (Grade 2): mentally add or subtract 10 or 100 to or from a number between 100 and 900.