Subtraction facts · −1
The Minus 1 Facts
Taking away 1: the number before. Every question in this game takes away 1.
Minus 1 chart
| Fact | Check by adding |
|---|---|
| 2 − 1 = 1 | 1 + 1 = 2 |
| 3 − 1 = 2 | 2 + 1 = 3 |
| 4 − 1 = 3 | 3 + 1 = 4 |
| 5 − 1 = 4 | 4 + 1 = 5 |
| 6 − 1 = 5 | 5 + 1 = 6 |
| 7 − 1 = 6 | 6 + 1 = 7 |
| 8 − 1 = 7 | 7 + 1 = 8 |
| 9 − 1 = 8 | 8 + 1 = 9 |
| 10 − 1 = 9 | 9 + 1 = 10 |
| 11 − 1 = 10 | 10 + 1 = 11 |
How to learn the −1 facts
Taking away 1 needs no counting. 9 − 1 is whatever comes before 9.
20 − 1 and 11 − 1 catch people out. Saying numbers backwards from 20 is good practice in itself.
Play the minus 1 game
Every question takes away 1
Free to play · no signup · works on phones, tablets and computers
Quick quiz
Keep going
Minus 1 FAQ
What's the easiest way to subtract 1?
Just say the number before. Taking away 1 needs no counting. 9 − 1 is whatever comes before 9.
How can a child check a subtraction fact?
Add back. If 12 − 1 = 11, then 11 + 1 should make 12. That's the second column in the chart.
Is Sumtown really free?
Yes. The whole game plays free in your browser, with no signup, no ads and no time limit. All fourteen mini games are in it. An iPhone app is on its way, and you can read what it will add.
An app is on its way
We're building a Sumtown app for iPhone with the parts that need a real app: offline play for car rides, a town map that remembers how far your child got, and a parent report on every fact. Until then, the whole game is free right here.
Coming soon on theApp Store