Addition and subtraction facts to 20: what children learn
By the end of Year 2, pupils in England should recall and use addition and subtraction facts to 20 fluently, and use them to derive related facts up to 100. 'Fluently' means quickly and accurately, without needing to count each time.
This is a sprint game: children type as many answers as they can in 60 seconds. The questions include straightforward facts (9 + 6 = ?), subtractions (17 − 8 = ?) and missing number forms (? + 5 = 13). Regular short sprints are one of the best ways to build fluency, and the timer shows progress clearly.
This topic covers the Year 2 statutory requirement in the National Curriculum in England (Number – addition and subtraction): pupils should be taught to “recall and use addition and subtraction facts to 20 fluently, and derive and use related facts up to 100”. Year 2 pupils are usually aged 6–7.
For families following US standards, the closest Common Core standard is 2.OA.B.2, which is taught in Grade 2.
How to play
How many can you answer in 60 seconds? Type the answer and press Enter. Questions keep coming for 60 seconds. Type each answer and press Enter, or choose Skip. Answers can be typed with or without commas.
Step by step
- Know the bonds to 10. Most facts to 20 can be built from bonds to 10. If you know 7 + 3 = 10, then 7 + 4 is one more: 11.
- Use doubles and near doubles. Doubles such as 6 + 6 = 12 are easy to remember. Near doubles follow: 6 + 7 is double 6 plus 1, which is 13.
- Bridge through 10. For 9 + 6, take 1 from the 6 to make 10, leaving 5: 10 + 5 = 15. For 15 − 7, take 5 to reach 10, then 2 more: 8.
- Derive bigger facts. Once 3 + 7 = 10 is known, so is 30 + 70 = 100 and 100 − 70 = 30. This is what the curriculum means by 'derive and use related facts up to 100'.
Worked examples
Example 1: 9 + 6 = ?
Working: 9 + 1 = 10, and 5 more is 15.
Answer: 15
Example 2: 13 − 8 = ?
Working: Count up from 8: 2 more makes 10, then 3 more makes 13. 2 + 3 = 5.
Answer: 5
Example 3: ? + 7 = 16
Working: 16 − 7 = 9. Check: 9 + 7 = 16.
Answer: 9
Common mistakes and how to fix them
- Rushing and typing an answer that is one out. Being one out often comes from counting on or back. Practise the bridging strategy instead.
- Getting stuck on missing number questions. Turn them into subtraction: ? + 7 = 16 is the same as 16 − 7.
- Knowing facts one way round only. Practise fact families. If you know 8 + 5, you know 5 + 8, 13 − 5 and 13 − 8.
Activities to try at home
- Do one 60-second sprint a day and keep a chart of scores. Beat your best, not your sibling.
- Play 'make 20' with playing cards (picture cards removed): turn two over and work out the total, or how many more to reach 20.
- Ask quick facts while waiting in queues or walking to school.
Ideas for the classroom
- Display a 'strategy wall' with bonds to 10, doubles, near doubles and bridging, and ask pupils which strategy they used.
- Use the printable worksheet as a timed starter, then mark it with the answer sheet.
- Pair pupils to make up missing number questions for each other.
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
What does fluency with facts to 20 mean?
Being able to answer facts such as 8 + 7 or 15 − 9 quickly and accurately, usually in a few seconds, without counting in ones.
How does the sprint score work?
You get one point for each correct answer before the timer runs out. Wrong answers show the right answer and move on. Stars are awarded for 6, 12 and 18 correct.
Can I type answers on a phone?
Yes. The answer box opens a number keyboard on most phones and tablets.