Strategies for Adding 7, 8, and 9
🦸♀️ 7, 8, and 9 are big numbers! But we have a secret superhero strategy to deal with them: making a 10!
Do this: Read the concept below, then try the quiz or activity.
Concept
When you need to add big single digits like 7, 8, or 9, counting on your fingers takes too long. Let's use our "Make 10" superpowers!
🎯 The "Make 10" Strategy: Example: Let's solve 8 + 5 = ? 1. Find the 10-maker: 8 is super close to 10. It only needs 2 more. (8 + 2 = 10) 2. Borrow from the other number: Take that 2 away from the 5. (Now the 5 becomes a 3). 3. Make 10! Give the 2 to the 8. Now you have 10 + 3. 4. Add to 10: 10 + 3 is easy! It's 13. So, 8 + 5 = 13.
This works perfectly for 9, too! 9 is just 1 away from 10. Example: 9 + 6 = ? Take 1 from the 6 (it becomes 5). Give it to the 9 (it becomes 10). Now you have 10 + 5. The answer is 15!
Try it
Let's practice the "Make 10" superhero strategy!
Instructions: Borrow from the smaller number to make a 10, then add the rest.
Problem 1: 9 + 4 = ? * Take 1 from the 4. Now the 4 is 3. * 9 becomes 10. * What is 10 + 3? ___ * Answer: 9 + 4 = ___
Problem 2: 8 + 6 = ? * 8 needs 2 to make 10. * Take 2 from the 6. What is left? ___ * 10 + ___ = ___ * Answer: 8 + 6 = ___
Problem 3: 7 + 5 = ? * 7 needs 3 to make 10. * Answer: ___
Problem 4: 9 + 8 = ? * (Hint: Make 10 out of the 9!) * Answer: ___