Year 1 missing number problems worksheet answers to download as PDF

These Year 1 missing number problems worksheet answers give a full worked solution to all 20 questions of the missing number problems worksheet. Try each question yourself first, then check your method step by step.

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Answer to Question 1
1. 8 − 3 = 5, so the missing number is 5. Check: 3 + 5 = 8.
2. 10 − 5 = 5, so the missing number is 5. Check: 5 + 5 = 10.
3. 12 − 7 = 5, so the missing number is 5. Check: 7 + 5 = 12.
4. 9 − 4 = 5, so the missing number is 5. Check: 5 + 4 = 9.
5. 13 − 6 = 7, so the missing number is 7. Check: 7 + 6 = 13.
Answer to Question 2
1. 8 − 3 = 5, so the missing number is 5. Check: 8 − 5 = 3.
2. 10 − 6 = 4, so the missing number is 4. Check: 10 − 4 = 6.
3. 14 − 9 = 5, so the missing number is 5. Check: 14 − 5 = 9.
4. 12 − 4 = 8, so the missing number is 8. Check: 12 − 8 = 4.
5. 16 − 10 = 6, so the missing number is 6. Check: 16 − 6 = 10.
Answer to Question 3
1. Add back: 5 + 4 = 9. The missing number is 9. Check: 9 − 4 = 5.
2. Add back: 3 + 7 = 10. The missing number is 10. Check: 10 − 7 = 3.
3. Add back: 9 + 2 = 11. The missing number is 11. Check: 11 − 2 = 9.
4. Add back: 8 + 6 = 14. The missing number is 14. Check: 14 − 6 = 8.
5. Add back: 12 + 5 = 17. The missing number is 17. Check: 17 − 5 = 12.
Answer to Question 4
1. 9 − 4 = 5. Check: 4 + 5 = 9.
2. 12 − 8 = 4. Check: 4 + 8 = 12.
3. 15 − 9 = 6. Check: 9 + 6 = 15.
4. 10 − 7 = 3. Check: 10 − 3 = 7.
5. 5 + 8 = 13. Check: 13 − 8 = 5.
Answer to Question 5
1. Add the two numbers on the left pan: start at 6 and count on 3: 7, 8, 9. So 6 + 3 = 9, and 9 balances the other side.
2. Work out the full side first: 4 + 6 = 10. The scales balance, so 5 + ? must also make 10. 5 + 5 = 10, so the missing number is 5.
3. 8 is the whole and 3 is one part. Take the part away from the whole: 8 − 3 = 5. The missing number is 5. Check: 3 + 5 = 8.
Answer to Question 6
1. Half of 8 is 4. 4 + 4 = 8.
2. Half of 12 is 6. 6 + 6 = 12.
3. Half of 18 is 9. 9 + 9 = 18.
4. Half of 20 is 10. 10 + 10 = 20.
Answer to Question 7
1. 6 + ? = 14.
2. 14 − 6 = 8 stickers.
3. 6 + 8 = 14. Correct.
4. 14 − 5 = 9. Sentence: 14 − 5 = ? and the answer is 9.
Answer to Question 8
1. Start with 15 cups, take some away, and 9 are left. The number sentence is 15 − ? = 9.
2. Find the missing number by counting on from 9 to 15: 10, 11, 12, 13, 14, 15. That is 6 steps, so the waiter took 6 cups away.
3. Put the cups back: the 9 on the tray plus the 6 taken away should make 15. 9 + 6 = 15, so the answer is correct.
4. The waiter brings back 4 cups, so add: 9 + 4 = 13 cups on the tray now.
Answer to Question 9
1. We do not know the start, then 7 are added and the total is 16. The number sentence is ? + 7 = 16.
2. Take the 7 added marbles away from 16: 16 − 7 = 9. Omar had 9 marbles to start with. Check: 9 + 7 = 16.
3. He starts with 16, loses some and has 10 left. The number sentence is 16 − ? = 10.
4. Count back from 16 to 10: 15, 14, 13, 12, 11, 10. That is 6 steps, so he lost 6 marbles. Check: 16 − 6 = 10.
Answer to Question 10
1. 8 − 5 = 3 goals.
2. ? + 7 = 12.
3. 12 − 7 = 5 goals.
4. The Reds scored 5 and the Blues scored 5. Neither: they scored the same.
Answer to Question 11
1. 10 − 6 = 4 apples.
2. 10 − 3 = 7 pieces of fruit.
3. ? = 6 − 3. (Start with 6 pears and take 3 away.)
4. 6 − 3 = 3 pears.
Answer to Question 12
1. 17 cars, some are sold and 8 are left. The number sentence is 17 − ? = 8.
2. Count on from 8 to 17: 2 steps to 10, then 7 more to 17. 2 + 7 = 9, so 9 cars were sold. Check: 17 − 9 = 8.
3. There are 8 cars, the shop gets some more, and then there are 13. The number sentence is 8 + ? = 13.
4. Count on from 8 to 13: 9, 10, 11, 12, 13. That is 5 steps, so the shop got 5 cars. Check: 8 + 5 = 13.
Answer to Question 13
1. Hana is 7, so there are 7 candles in all. 3 are in the pink box and we do not know the blue box: 3 + ? = 7.
2. Count on from 3 to 7: 4, 5, 6, 7. That is 4 steps, so there are 4 candles in the blue box. Check: 3 + 4 = 7.
3. Her brother is 5, so there are 5 candles. One box has 2: 2 + ? = 5.
4. Count on from 2 to 5: 3, 4, 5. That is 3 steps, so the second box has 3 candles. Check: 2 + 3 = 5.
Answer to Question 14
1. 9 + 1 = 10. So ? + 5 = 10, and ? = 5.
2. 6 + 4 = 10. So ? + 3 = 10, and ? = 7.
3. 12 − 2 = 10. So 4 + ? = 10, and ? = 6.
4. 7 + 7 = 14. So 20 − ? = 14, and ? = 6.
Answer to Question 15
1. ? + 4 = 11.
2. 11 − 4 = 7 coins.
3. 6 + 4 = 10, not 11. So her brother is wrong. Lily had 7 coins.
4. 11 − 3 = 8 coins.
Answer to Question 16
1. 13 − 6 = 7.
2. 13 − 5 = 8.
3. 8 pairs with 5, and 7 pairs with 6.
4. 6 + ? = 13 (? = 7) and 5 + ? = 13 (? = 8).
Answer to Question 17
1. 20 − ? = 11.
2. 20 − 11 = 9 cherries.
3. 11 − 5 = 6 cherries.
4. 9 + 5 = 14 cherries. Check: 20 − 14 = 6.
Answer to Question 18
1. There were 20 books, some went home and 12 are left. The number sentence is 20 − ? = 12.
2. Count on from 12 to 20: 8 steps (13, 14, 15, 16, 17, 18, 19, 20). So 8 books were taken home. Check: 12 + 8 = 20.
3. The librarian adds 6 books: 12 + 6 = 18 books on the shelf.
4. No, she is not right. There are 18 books, and 18 is less than 20 because it comes before 20 when we count. There are 2 fewer than 20.
Answer to Question 19
1. 10 − 3 = 7.
2. A is 7. B + 7 = 12, so B = 12 − 7 = 5.
3. C − 5 = 2, so C = 5 + 2 = 7.
4. 7 + 5 + 7 = 19.
Answer to Question 20
1. 5 + 9 = 14. This is the only pair of different cards: 5 and 9.
2. 2 + 11 = 13, which is not 14. They make 13.
3. The cards 2, 7 and 11 have no partner. (2 would need 12, 7 would need another 7, 11 would need 3.)
4. 7 + 9 = 16.

How to use these Year 1 missing number problems worksheet answers

First, try every question on the worksheet without looking. Then compare your working with the solution line by line, not only the final answer. When your answer is different, find the first step that changes, because that is where the mistake is. After that, read the matching part of the missing number problems lesson again. Finally, check that the method is secure with the quiz or the test.

Also, the Year 1 missing number problems worksheet answers are available as a PDF, so you can mark printed work quickly. Moreover, all the pages of this chapter work together, so you can move between them at any time. For example, many pupils read the lesson on Monday, practise on Wednesday and test themselves on Friday. In short, these Year 1 missing number problems worksheet answers show every step, so nothing is left unexplained.