To solve 8 + 5, break 5 into 2 + 3. Then 8 + 2 = 10, and 10 + 3 = 13. Using 10 as a benchmark makes the problem simpler. This strategy relies on knowing number bonds to 10 and is a bridge to place-value understanding.
You already know your number bonds to 10 — the pairs of numbers that add up to exactly 10, like 6 + 4, 7 + 3, and 8 + 2. And you've practiced adding numbers within 20. Making ten is a strategy that combines both of those skills into a powerful shortcut: instead of counting all the way from 8 up to 13 in your head, you can use 10 as a stepping stone.
Here's how it works. Suppose you need to add 8 + 5. Ten is a friendly, easy number — you know what 10 looks like, and you know that 10 + anything is simple. So instead of adding 8 and 5 directly, you ask: how much does 8 need to become 10? It needs 2 more. So you "borrow" 2 from the 5, making 8 into 10. Now the 5 has become 3 (because you used 2 of it). The new problem is 10 + 3, which is easy: 13. You've used your number bond knowledge (8 + 2 = 10) to turn a tricky problem into a simple one.
The reason 10 is such a useful stopping point is that our number system is built around tens. Once you reach 10, you're starting a new group — the tens place. This is why adding to 10 feels natural and quick. When you know that 10 + 6 = 16, or 10 + 7 = 17, you're already thinking in place value: one ten and some ones. Making ten is practice for the way our whole number system is organized.
Try it with other problems: 9 + 4 (9 needs 1 more to reach 10, so take 1 from the 4, leaving 3; now you have 10 + 3 = 13). Or 7 + 6 (7 needs 3 more, take 3 from 6, leaving 3; 10 + 3 = 13). The strategy always has the same three steps: figure out what your bigger number needs to reach 10, break that amount off the smaller number, and then add what's left to 10. With practice, you won't need to think through all the steps — your brain will jump straight to the answer.