The core idea is simple: 10 is a “friendly” number. It is much easier for our brains to add a number to 10 (like $10 + 4$) than it is to add two different single digits (like $7 + 7$).
By breaking down one of the numbers to reach 10 first, the remaining addition becomes a breeze.
Let’s look at the examples from our worksheet to see the logic in action:
| Original Problem | The Logic (Making a 10) | Final Answer |
| $9 + 6$ | 9 needs 1 more to be 10. Take 1 from the 6. Now you have $10 + 5$. | 15 |
| $8 + 5$ | 8 needs 2 more to be 10. Take 2 from the 5. Now you have $10 + 3$. | 13 |
| $7 + 6$ | 7 needs 3 more to be 10. Take 3 from the 6. Now you have $10 + 3$. | 13 |
| $6 + 5$ | 6 needs 4 more to be 10. Take 4 from the 5. Now you have $10 + 1$. | 11 |
A great way to support this strategy is to have students memorize their “Doubles.” When a student knows that $8 + 8 = 16$ instantly, they can use that as an anchor.
If they know $8 + 8 = 16$, then $8 + 7$ must be one less (15). Our worksheet includes a handy “Note” section with these doubles to help build that foundational speed.