K-5 friendly lesson

Try one idea, then jump into the activity.These lessons are designed to feel short, friendly, and easy to follow.

Complete the Addition Sentence - Sums up to 20

🧩 The missing piece! Time to use subtraction to find the hidden addend in these big addition sentences.

Lesson 5

Concept

You know how to do this! But now the numbers go all the way up to 20. 🎯 **The Subtraction Flip Strategy:** If you have a missing piece in an addition sentence, flip it into a subtraction sentence! **Example: 11 + ___ = 18** * Turn it around: 18 - 11 = ? * Let's subtract: 18 - 11 = 7. * So, the missing piece is 7! (11 + **7** = 18). 🎯 **The Count On Strategy:** If the numbers are close, just count up! **Example: 15 + ___ = 19** * Start at 15. Count on to 19: "16, 17, 18, 19". * That took 4 steps. * The missing piece is 4! (15 + **4** = 19).

Try it

Find the hidden numbers! **Instructions:** Use subtraction or count on to find the missing addend. **Problem 1:** 12 + ___ = 17 * (Try counting on from 12!) * Answer: ___ **Problem 2:** ___ + 9 = 15 * (Try the flip! 15 - 9 = ?) * Answer: ___ **Problem 3:** 8 + ___ = 16 * (Wait! I know this double!) * Answer: ___ **Problem 4:** 14 + ___ = 20 * Answer: ___