Turn your own sums into addition and subtraction flash cards to 20
Photograph a worksheet or paste your notes, and DeckOwl builds flashcards of sums and differences within 20 that come back at the right time.
Why build your own addition and subtraction cards
A printed worksheet of sums is used once, but a stack of addition and subtraction flash cards to 20 built from the problems your child is actually learning gets reviewed until the facts are automatic.
- Works from photos of worksheets, so you do not have to retype problems.
- Cards cover sums and differences within 20, including the teen numbers.
- Spaced repetition repeats the facts a child misses more often.
- Export to PDF or CSV on the Plus plan when you want printed or shared sets.
Built from your material
Upload a photo of a worksheet, a PDF, or typed notes. Text recognition reads the problems so the cards match what your child is working on.
Spaced repetition
Cards the learner misses come back sooner, and familiar facts appear less often, so practice time goes to the facts that need it.
Print or export when you need to
Study in the browser on the free plan. Plus adds PDF and CSV export, so you can print a set or bring it into another app.
How it works
Upload your sheet or notes
Add a photo of a worksheet, a PDF, a DOCX, or plain text with the sums you want to practice.
Review the generated cards
Check that each sum has the right answer, then remove or edit any card you want to change.
Study a little each day
Practice in short sessions. The spaced repetition schedule brings back the facts that are still shaky.
Upload a photo of the worksheet or type in the pattern you want, such as 8 plus 7 or 15 minus 9, and DeckOwl writes a front and back for each fact. Fronts show the problem and backs show the answer, so a parent or teacher can check them quickly.
The free plan includes 3 generations per month and studying in the browser with no credit card needed. Plus, at $39 per year or $7.99 per month, removes the generation limit and adds PDF export for printing.
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Frequently asked questions
How often should a child practice addition facts to 20?
Short daily sessions of about 5 to 10 minutes work better than one long session. Spaced repetition also brings back missed facts sooner, so practice stays focused.
How do I teach subtraction to 20 with flash cards?
Pair each subtraction card with its related addition fact, such as 14 minus 6 with 6 plus 8 equals 14, so children see how the operations connect. Start with sums to 10 and add the teen numbers once those feel steady.
Can I print my flash cards?
Printing needs a PDF export, which is included in the Plus plan at $39 per year or $7.99 per month. The free plan lets you study the cards in your browser.
Is there a free plan?
Yes. The free plan includes 3 generations per month and browser study, and you do not need a credit card to start.
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