Printable Subtracting 8 Flash Cards
Subtracting 8 reverses the cleanest trick in addition: where +8 took 2, −8 gives 2 back — take the whole 10 away and return 2, so 14 − 8 is 4 + 2 = 6. These fold-over flashcards cover 9 − 8 through 20 − 8.
How to Use These Flash Cards
Chant the reverse move: "minus ten, plus two." For 17 − 8: back 10 to 7, give 2 back — 9. Think-addition is the other door (8 + what makes 17?), and 16 − 8 = 8, the double's half, should be instant before the rest are pushed. The deck tops out at 20 − 8 = 12.
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 minus-ten-plus-two trick?
Since 8 is 10 minus 2, taking 8 away is the same as taking 10 and giving 2 back: 13 − 8 is 3 + 2 = 5. One fixed move answers the whole family, just like "8 takes 2" did for addition.
How should 15 − 8 be attacked?
Either door: minus-ten-plus-two gives 5 + 2 = 7, or think-addition asks 8 + what makes 15 (the +8 deck answered 7). Stubborn cards usually yield once both doors are open.
Why does this deck run to 20 − 8?
Each deck holds the twelve facts with answers 1 through 12, so subtracting 8 spans minuends 9 through 20. Reaching past the teens is a bonus — 20 − 8 = 12 previews the two-digit subtraction ahead.