K-5 friendly lesson
One small step at a time.Read the idea, try the activity, and celebrate each win as you go.
Adding Three Numbers
➕➕➕ Adding three numbers at once? No problem! The secret is to look for friends first. Find a pair of numbers that are easy to add together, like friends that make 10!
Do this: Read the concept below, then try the quiz or activity.
Lesson 40 of 180
Concept
When you have to add three numbers, like 4 + 7 + 6, you don't have to add them in order. You can rearrange them to make the problem easier!
🎯 The "Find Friends First" Strategy:
1. Look at all three numbers: For example, 4 + 7 + 6.
2. Find a pair of "friends": Look for numbers that make 10, or a double.
* In 4 + 7 + 6, the numbers 4 and 6 are friends! They make 10.
3. Add the friends first: 4 + 6 = 10.
4. Add the leftover number: Now just add the 7.
* 10 + 7 = 17.
5. The Answer: So, 4 + 7 + 6 = 17. This is much easier than adding 4+7 first!Another Example: Let's solve 5 + 8 + 5. * Do you see the friends? The double 5 + 5! * Add them first: 5 + 5 = 10. * Now add the leftover 8: 10 + 8 = 18.
Try it
Let's practice finding the friends!
Instructions: For each problem, circle the two "friend" numbers first, add them, and then add the last number.
Problem 1: 8 + 2 + 5 * Circle the friends: 8 + 2 * 8 + 2 = 10 * 10 + 5 = ___
Problem 2: 7 + 6 + 3 * Find the friends that make 10. * ___ + ___ = 10 * 10 + ___ = ___
Problem 3: 4 + 5 + 4 * Find the double. * ___ + ___ = ___ * ___ + 5 = ___
Your Turn! 4. 9 + 5 + 1 = ___ 5. 6 + 8 + 4 = ___ 6. 2 + 7 + 8 = ___
Word Problem Challenge: 7. A monkey ate 7 bananas in the morning, 3 bananas in the afternoon, and 5 bananas at night. How many bananas did he eat in total? * Find the friends first!