Addition Fundamentals Summary

Arithmetic · Axiom Academy

SUMMARY Addition Fundamentals Summary Key takeaways from Unit 2 — what addition means, the words we use for it, and the strategies that make adding faster. Addition combines groups to find a total. The answer is called the sum ; the numbers being added are the addends . Order doesn't matter — addition is commutative . Strategies like making ten, doubles, and near doubles make adding faster. Addition puts groups together to find a total. The numbers you combine are the addends , and the result is the sum . When to use: any time you're combining amounts into one total. Key property: order doesn't matter — it's commutative. Find what one number needs to reach 10, break the other number apart to give it, then add 10 plus the leftover. When to use: works well for 8+ and 9+ facts. Watch out for: break apart the other number, not the one you're filling to 10. A double is the same number plus itself. They're easy to remember and to picture, and they're the foundation for near doubles. Pattern: every double has an even sum. Why it matters: knowing doubles unlocks the near-doubles shortcut. When two numbers are 1 apart, start from the double you already know, then add or subtract 1. When to use: numbers that are 1 apart, like 6+7. How: use the nearby double, then adjust by 1. Addition is combining — when we add, we put groups together. Strategies make it easier — making ten, doubles, and counting on help us add faster.

This is the written version of the interactive lesson above. See the full Arithmetic course.