Subtraction Within 20 Worksheets
Free printable subtraction within 20 worksheets with answer keys. Subtraction from numbers up to 20, including facts that cross ten, such as 15 − 8 and 13 − 6.
Using this page
Subtraction from numbers up to 20, including facts that cross ten, such as 15 − 8 and 13 − 6. Grade 1 children in the Common Core subtract within 20, and Australian students build the same facts in Year 1 and Year 2. The sheet mixes easier questions with the bridging ones that need a strategy. Suits around Year 1 and Year 2 in Australia and Grade 1 in the US (Common Core 1.OA.C.6), but use whatever level fits the child.
Tips
- Keep sessions short: one sheet of 10 to 20 questions a day beats a long session once a week.
- Mark the sheet together with the answer key and talk about the mistakes; each one shows what to practise next.
- Move to the next sheet when a child gets almost every question right without counting on fingers.
- Where it is offered, use the column layout for written methods and the across layout for mental strategies.
Worked example
15 − 8. Count back to ten first: 15 − 5 = 10, then take away the other 3: 10 − 3 = 7. So 15 − 8 = 7. Or think addition: 8 + 7 = 15.
Common mistakes
Taking 3 from 6 instead of 6 from 13, giving an answer of 3 for 13 − 6. Bridge through ten: 13 − 3 = 10, then 10 − 3 = 7.
Losing count when counting back more than five. Bridging through ten is more reliable.
How to use this generator
Choose the options above the sheet: the number of questions and the settings for this kind of worksheet. Every change makes a new sheet straight away, and New worksheet gives a different set of questions with the same settings.
Each sheet has a worksheet number printed at the top. Type the same number later, or keep the page link, to print exactly the same questions and answer key again. Leave Answer key page ticked to print the answers on a second page, then press Print. Every printed page carries the makekite logo and web address.
Common questions
How do fact families help?
Knowing 8 + 7 = 15 gives 15 − 7 = 8 and 15 − 8 = 7 for free. Practise addition and subtraction side by side.
How many questions should a child do?
Ten to twenty is plenty for daily practice. The 100-question drill sheet is for short timed practice once or twice a week.
Can I print the same worksheet again?
Yes. Note the worksheet number printed at the top, or keep the link in your browser's address bar, which ends with that number. Entering it later gives the same questions and answers.
Is it free?
Yes. There is no sign-up, and nothing you choose is sent anywhere: the sheets are made in your browser.