Addition Table for 1
Each row adds 1 to numbers 1 through 12. Addition tables help build number sense and make mental math faster.
Adding 1 flips parity: every even grows into an odd and every odd into an even — 4 + 1 = 5. The nearest round ten is 10, just 9 away: 1 + 9 = 10. Every fact runs backward for free: from 1 + 6 = 7 comes the subtraction fact 7 − 1 = 6.
| Addend | Sum |
|---|---|
| 1 + 1 | 2 |
| 1 + 2 | 3 |
| 1 + 3 | 4 |
| 1 + 4 | 5 |
| 1 + 5 | 6 |
| 1 + 6 | 7 |
| 1 + 7 | 8 |
| 1 + 8 | 9 |
| 1 + 9 | 10 |
| 1 + 10 | 11 |
| 1 + 11 | 12 |
| 1 + 12 | 13 |
Frequently asked questions
What are the addition facts for 1?
Adding 1 to each number 1 through 12 gives every fact above, from 1 + 1 = 2 up to 1 + 12 = 13.
What is 1 + 7?
1 + 7 = 8.
What is the fastest way to add 1 mentally?
Split 1 into tens and ones, add the tens first, then the ones. For example 1 + 6 = (1 + 5) + 1 = 6 + 1 = 7.