Printable Subtracting 9 Flash Cards
Subtracting 9 mirrors the adding-9 trick: take ten away, then give one back — 15 − 9 is 5 + 1 = 6. The answers follow a pattern as well: on every teen card, the answer is one more than the minuend's ones digit. These fold-over flashcards cover 10 − 9 through 21 − 9.
How to Use These Flash Cards
Run the chant on every flip — "minus ten... plus one" — until it collapses into recall: 17 − 9 is 7 + 1 = 8. Show the ones-digit pattern (13 − 9 = 4, 14 − 9 = 5, 15 − 9 = 6) and let the child predict a few answers before flipping — predicting is faster practice than reciting.
How to Cut and Fold
- Print the PDF single-sided on plain paper or light cardstock.
- Cut along the solid lines to separate the cards.
- Fold each card along the dashed center line so the answer sits behind the question, and turn the card over like a page to check.
- Optional: a dab of glue inside the fold makes a sturdy double-thick card.
Frequently Asked Questions
What is the take-ten-give-one trick?
Nine is one less than ten, so subtracting 9 equals subtracting 10 and adding 1 back: 16 − 9 is 6 + 1 = 7. It converts the hardest-looking family into the easiest.
Why is each answer one more than the ones digit?
Because minus 10 keeps the ones digit and plus 1 raises it by one: 15 − 9 = 6, one more than the 5. For 20 and 21 the same logic reads off the tens: 21 − 9 = 12.
Should −9 be drilled right after +9?
Yes — the tricks are mirror images (add ten take one, take ten give one), and running the decks together makes the ten-based thinking stick as one idea instead of two.