Mini Minds Hub · Free printable
Missing Numbers in Additions: Free Printable Worksheet for Year 2
- ForYear 2
- StageKey Stage 1
- CostFree
- FormatPrintable PDF
Missing Numbers in Additions is a free printable maths worksheet for Year 2 (ages 6 to 7). Children find the other part in an addition, such as a sum with a gap in the middle or at the front. 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
Each question on the sheet is an addition with one number missing, and there is space to write the answer. The gap sometimes comes after the plus sign and sometimes before it. Children begin with small totals and move on to bigger totals, including tens and a total of 100. They think about the part they know, the total, and what is needed to join them.
- 7 + ___ = 12
- ___ + 6 = 15
- 20 + ___ = 50
- 14 + ___ = 21
- 9 + ___ = 17
- ___ + 25 = 45
- 36 + ___ = 60
- 40 + ___ = 100
A worked example
8 + ___ = 13
This is a different question from the ones on the sheet. It shows two ways to think about a missing number.
Method 1: count on- Start at the number you know, 8. Say it in your head but do not count it.
- Count on until you reach 13: 9, 10, 11, 12, 13. Put up a finger for each number you say.
- You said five numbers, so the missing number is 5.
- Start at 8. It needs 2 more to reach 10.
- From 10 to 13 is 3 more.
- Add the jumps: 2 + 3 = 5. The missing number is 5.
Ways to find a missing number
Count on
Start from the number you know and count up to the total. Use a number line, fingers or counters. Keep track of how many steps you take. That count is the missing number.
Think of a number bond
Many missing number sums are really number bonds. Ask, "What goes with this number to make the total?" Knowing pairs that make 10 and 20 makes this much quicker.
Use tens
When the numbers are tens, think in tens. Say "three tens and how many tens make five tens?" Counting in tens is easier than counting in ones.
Check by adding
Put the answer in the gap and add again. If the two parts make the total, the answer is right. This habit helps children spot their own slips.
Why missing number sums matter
A missing number sum asks children to look at addition from a new angle. Instead of adding two numbers to get a total, they are given the total and one part, and they must find the other part. This builds a flexible sense of how parts and wholes fit together, which is a key idea in early number work.
The equals sign also gets a proper workout. Children often see it as a sign meaning "the answer comes next". In a sum with a gap, it shows that both sides have the same value. Seeing this helps later with subtraction, algebra and balancing number sentences.
Skills and curriculum link
- Missing number sums
- Number bonds
- Counting on
- Adding tens
- Checking answers
Ideas that help with missing numbers
- Parts and wholesA total is made of parts. If you know the total and one part, the other part is what is left to find.
- Order does not change the totalAdding two numbers in either order gives the same total. So a gap at the front can be treated like a gap at the back.
- Addition and subtraction are linkedFinding the missing part can be done by counting on, or by taking the known part away from the total. Both routes lead to the same number.
- Tens behave like onesFacts about small numbers can be used for tens. If children know how ones fit together, they can use the same idea with tens.
Key words
- Missing numberThe number that is not shown. It is the one you have to find.
- TotalThe whole amount you get when you put the parts together.
- PartOne of the numbers that are added together to make a total.
- Number bondTwo numbers that add together to make a given total.
- Count onStart from one number and count up to reach another.
- EqualsHas the same value as. Both sides of an equals sign must match.
How to use it
- Print both pages. Page 1 is for your child. Keep page 2, which has the notes and answers.
- Read the first question aloud. Ask, "What number are we looking for?" Point to the gap.
- Let your child choose how to work: fingers, a number line, counters or number bonds. There is no one right way.
- Ask them to check by putting the answer in the gap and adding. Then look at page 2 together.
- Come back another day and try the tricky ones again. Repeating a familiar sheet builds confidence.
Help, stretch and game ideas
If it feels too hard
Use a number line or counters. Start at the number you know and count on until you reach the total. Put a counter down for each count, then count the counters. Try the questions with small totals first and come back to the others later.
To stretch confident children
Make up four missing number sums with a total of 100 for a partner. Include at least one with the gap at the front. Swap sheets and solve each other's. Then check by adding each answer back in.
Make it a game
Take turns choosing a total and finding pairs that make it. Write each pair as a sum with a gap, then ask your partner to fill it in. Score a point for each correct answer. First to ten points wins.
Mistakes to watch for
Watch forA child adds the two numbers they can see. For 5 + ___ = 9, they write 14.
Try thisRead the sum aloud as "5 and how many more make 9?" Show 5 counters, then add more one at a time until there are 9.
Watch forA child counts the start number as the first step, so the answer is one too big.
Try thisSay the start number, then count on with fingers. Only the new numbers get a finger. Check by adding the answer back in.
Watch forA child freezes when the gap is at the front, as in ___ + 4 = 10.
Try thisRemind them that adding can be done in either order. Ask them to imagine the sum written as 4 + ___ = 10, then solve it.
Talk about it
- What is the sum asking us to find?
- How do you know your answer is right?
- Can you find the missing number a different way?
- What happens if the gap is at the front instead of the back?
- Which sums were quick for you, and why?
- Can you make up a missing number sum for me?
Take it off the page
Counter hunt
Choose a total, such as 10, and count out that many counters together. Your child closes their eyes while you hide some counters under a cup. They count the counters they can see, work out how many more make the total, then lift the cup to check.
Number line in chalk
Draw a big number line outside with chalk. Pick a start number and a total. Your child hops along the line from the start number to the total and counts their hops. That count is the missing number.
Shop at home
Make small price tags for toy items, using whole pence. Say you have some coins and need a total. Ask how many more pence are needed to buy an item. Use small totals and real coins to help.
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 counters or a number line and ask what they notice. Praise the thinking, not only the answer.
Teachers
Use it as a starter, plenary, early finisher task or homework after teaching number bonds and missing number problems. Page 2 gives support and stretch ideas for mixed ability groups, and the answers make marking quick.
Home educators
Pair it with everyday talk about parts and totals, such as how many more cups are needed to make a set. It is free to print again for brothers and sisters or for revision a few weeks later.
Where this fits in learning
Before this, children learn to count, to add two numbers to find a total and to know pairs that make 10. They meet the equals sign and learn that it means both sides are the same. These steps make missing number sums feel like a natural next move.
After this, children use the same thinking in subtraction, in bigger numbers and in word problems. In the National Curriculum for England, this sits within the number strand on addition and subtraction. Later work includes missing number problems with more complex numbers and with other operations.
Questions parents and teachers ask
- What age is Missing Numbers in Additions for?
It is written for Year 2 (ages 6 to 7), in Key Stage 1. Some younger children who know their number bonds may enjoy it, and older children can use it as revision.
- What will children practise?
They practise finding the missing number in an addition by thinking of the other part. This uses number bonds, counting on and adding tens, and checking answers by adding them back in.
- How long does it take?
It takes about 10 minutes. Some children will be quicker and some will want more time. Page 2 has ideas for making it shorter with help, or longer with the stretch task.
- What if it feels too hard?
Use a number line or counters and count on from the first number. Start with the questions with smaller totals and come back to the harder ones another day. Doing the first one together also helps.
- 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.
- Is this a screen free activity?
Yes. It needs only paper and a pencil, so it works well for quiet time, rainy days and school holidays. It also gives children practice in thinking and writing by hand.
- Can teachers and home educators use it?
Yes. Teachers can use it as a starter, plenary, early finisher task, homework or table activity. Home educators and tutors can use it alone or as part of a wider maths plan. It needs no preparation beyond printing.
Preview the full PDF
Made by Jaques of London, making games for families since 1795. A printable supports classroom learning and does not replace a teacher.