Mini Minds Hub · Free printable
Adding 9 and 11 Mentally: Free Printable Worksheet for Year 3
- ForYear 3
- StageKey Stage 2
- CostFree
- FormatPrintable PDF
Adding 9 and 11 Mentally is a free printable maths worksheet for Year 3 (ages 7 to 8). Children add 9 or 11 to a two digit number by adding ten, then adjusting by one. It takes about 10 minutes, needs only a pencil, and page 2 gives the grown up notes, help, a stretch idea and the answers.
It comes from the Mini Minds Hub, the free library of printables from Jaques of London, the British games and toy company that has been making games for families since 1795. Print both pages, give page 1 to your child and keep page 2 for yourself. Black and white printing works well.
What is on the sheet
The sheet has numbered questions, each with space for the answer. Every question asks children to add 9 or 11 to a two digit number. Some questions add 9 and others add 11, so children have to stop and think which adjustment to make. The aim is to answer in their head first, then write the answer down. Children practise one clear mental strategy until it feels quick and natural.
- 34 + 9 =
- 56 + 9 =
- 27 + 11 =
- 48 + 11 =
- 75 + 9 =
- 63 + 11 =
- 88 + 9 =
- 19 + 11 =
A worked example
42 + 9 = ?
This is a different question from the ones on the sheet. It shows the idea of adding ten, then adjusting. Adding 11 works in a similar way, but the adjustment goes the other way.
Method 1: add ten, then take one away- 9 is one less than 10, so add 10 first: 42 + 10 = 52.
- You added one too many, so take 1 away: 52 take away 1 is 51.
- Find 42 on the hundred square.
- Jump down one row to add ten. You land on 52.
- Step back one square to the left. You land on 51.
How the add ten and adjust trick works
Nine is close to ten
9 is just one less than 10. Adding 10 is easy because only the tens digit changes. So children add the friendly number first, then fix the small difference.
Eleven is one more than ten
11 is 10 and 1 more. Children add ten, then add one more. It is the same idea as adding 9, but the adjustment goes up instead of down.
Adjust in the right direction
Ask, "Did I add too much or too little?" For 9, ten is too much, so take one back. For 11, ten is too little, so add one more.
Say it out loud
Talking through each step helps the method stick. Try, "add ten, then take one away." Saying the steps makes them easier to remember and easier to explain.
Why learn to add near multiples of ten?
Numbers that sit just below or just above a multiple of ten come up all the time. Prices, distances and scores often end in 9 or 1. When children can add ten quickly, they can use that skill to handle these numbers without writing anything down.
This is a good example of a mental strategy. Instead of counting in ones, children change a hard sum into an easier one and then fix it. That habit of choosing a smart method, rather than the slowest one, is useful across the whole of maths.
Skills and curriculum link
- Mental addition
- Adding ten
- Adjusting by one
- Number sense
- Explaining thinking
This sheet supports the area below. It is matched to the published England framework. Please check it against your own school plan.
| Framework | Subject or area | Strand | Year |
|---|---|---|---|
| National Curriculum (England) | Maths | Addition and subtraction | Year 3 |
What children will be able to do
- I can add 9 by adding 10 and taking away 1.
- I can add 11 by adding 10 and adding 1.
- I can add in my head.
Ideas that make this easier
- Ten moreAdding ten changes the tens digit and leaves the ones digit the same. Children who know this can add ten without counting.
- Nearly ten9 is one less than 10 and 11 is one more than 10. Spotting this is the key to the whole sheet.
- Check the directionAdding 9 gives a little less than adding 10. Adding 11 gives a little more. This helps children spot answers that cannot be right.
- Use a hundred squareOn a hundred square, moving down one row adds ten. Moving left or right by one square adjusts the answer.
Key words
- Mental mathsWorking out an answer in your head, without counting on fingers or writing a long sum.
- AdjustMake a small change to fix your answer after using an easier number.
- Ten moreThe number you get by adding 10. The tens digit goes up by one.
- TotalThe answer when you add numbers together.
- Tens and onesThe two parts of a two digit number. 35 is 3 tens and 5 ones.
- Hundred squareA grid of the numbers 1 to 100 in rows of ten. Moving down one row adds ten.
How to use it
- Print both pages. Page 1 is for your child. Keep page 2, which has the notes and answers.
- Set aside about 10 minutes. Work through the first question together and say each step out loud.
- Ask your child to answer in their head first, then write the answer down.
- Check against the answers on page 2. Ask, "How did you work that out?" The reasoning matters as much as the answer.
- Come back to the sheet another day. Repeating a familiar activity builds confidence and speed.
Help, stretch and game ideas
If it feels too hard
Give your child a hundred square. For adding 9, find the number, jump down one row to add ten, then step back one square. For adding 11, jump down one row, then step one square to the right. Do the first few together.
To stretch confident children
Try adding 19 and 21 to a two digit number using the same idea. Add 20, then adjust by one. Ask your child to explain why it works. Then try adding 29 and 31 to a number of their choice.
Make it a game
Roll a die twice. The first roll is the tens digit and the second roll is the ones digit. Add 9 or 11 as fast as you can. Take turns, and score a point for each correct answer.
Mistakes to watch for
Watch forA child adds ten to 25 and writes 35 for 25 + 9, forgetting to take one away.
Try thisAsk, "Is 9 more or less than 10?" Then say the steps together: add ten, then take one away to get 34.
Watch forA child adds ten to 25, then takes one away for 25 + 11 and writes 34.
Try thisRemind them that 11 is more than 10. After adding ten, they need to add one more to reach 36.
Watch forA child adds ten to 42 but changes the ones digit, writing 43 instead of 52.
Try thisUse a hundred square or draw tens as sticks. Show that adding ten moves down a row and changes the tens digit.
Talk about it
- How do you add 9 to a number quickly?
- What is the trick for adding 11?
- Why do you add ten first?
- How do you know whether to take one away or add one?
- Can you show me with a number of your choice?
- Could you use the same idea for adding 19? What would change?
Take it off the page
Chalk hundred square
Draw a big hundred square outside with chalk. Pick a starting number, then hop down a row and step left or right to add 9 or 11.
Pretend shop
Label toys or tins with two digit prices. Pick one and add 9p or 11p for a pretend delivery fee. Work out the new price in your head.
Number line walk
Lay out ten sheets of paper in a line, each showing a multiple of ten. Walk to the nearest ten and talk about the small step needed to land on the answer.
Who it is for
Parents
Sit beside your child for the first question, then let them lead. About 10 minutes is plenty. If they get stuck, offer a hundred square and ask them to point to each jump. Praise the thinking, not only the answer.
Teachers
Use it as a starter or plenary after teaching mental addition, as an early finisher task or as supply cover. It needs no preparation beyond printing. Page 2 has support and stretch ideas for mixed ability groups, and a set of answers for quick marking.
Home educators
Print it as part of a wider maths plan. It pairs well with a hundred square on the wall and everyday talk about prices and scores. You can print it again for brothers and sisters, or revisit it a few weeks later as revision.
Where this fits in children's learning
Before this sheet, children learn to add and subtract ten from a two digit number and to recognise how place value works. Knowing number bonds to 10 also helps. These skills make adding ten, then adjusting, feel much more natural.
After this sheet, children can use the same idea with other numbers close to a multiple of ten, such as 19, 21, 29 and 31. They can also build on it with other mental strategies for addition and subtraction, in line with the Year 3 addition and subtraction strand.
Check it worked
Ask these when the sheet is finished. Listen for the reasoning, not just the answer.
- How do you add 9 to a number quickly?
- What is the trick for adding 11?
- Can you show me with a number of your choice?
Questions parents and teachers ask
- What age is Adding 9 and 11 Mentally for?
It is written for Year 3 (ages 7 to 8), in Key Stage 2. Children who are secure with adding ten to a two digit number will find it easiest. Younger or less confident children can use a hundred square for support.
- What will children practise?
Children practise adding 9 or 11 to a two digit number in their head. They add ten first, then adjust by one. This builds mental maths, number sense and the habit of explaining how they reached an answer.
- How long does it take?
It takes about 10 minutes for one child. Try to answer in your head first, then write the answer down. Work through the first question together, then let your child try the rest alone.
- What if it feels too hard?
Give your child a hundred square. They can jump down one row to add ten, then step left or right by one square to adjust. Do the first few together, and come back to the sheet another day.
- Is it free?
Yes. It is free to print for home and classroom use. You can print it again for brothers and sisters, or for revision a few weeks later. Black and white printing on plain A4 paper works well.
- Can teachers use it in class?
Yes. Teachers can use it as a starter, plenary, early finisher task, homework or table activity. It needs no preparation beyond printing. Page 2 has support and stretch ideas for mixed ability groups and the answers.
- Is it a screen free activity?
Yes. It needs only paper and a pencil, so it works well for quiet time, rainy days and school holidays. Children think, talk and write by hand, which gives their eyes a rest from screens.
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Made by Jaques of London, making games for families since 1795. A printable supports classroom learning and does not replace a teacher.