K-5 friendly lesson
Try one idea, then jump into the activity.These lessons are designed to feel short, friendly, and easy to follow.

Which Sign Makes the Number Sentence True?

šŸ•µļøā€ā™‚ļø Oh no! Someone stole the math signs! You have to look at the numbers and the answer to figure out if it was a PLUS or a MINUS.

Lesson 4

Concept

These puzzles are completely missing their operation signs (+ or -)! You have to be a detective to put them back. šŸŽÆ **The Size Trick:** Look at the starting number and the answer. **Example: 12 ___ 4 = 16** 1. Start: 12. Answer: 16. 2. Did the number get BIGGER or SMALLER? 3. It got bigger! The only way to make a number bigger is to **ADD (+)**. 4. Let's test it: 12 + 4 = 16. It works! **Example: 15 ___ 5 = 10** 1. Start: 15. Answer: 10. 2. Did it get bigger or smaller? It got smaller! 3. The only way to make it smaller is to **SUBTRACT (-)**. 4. Let's test it: 15 - 5 = 10. It works!

Try it

Find the missing signs! **Instructions:** Did the number get bigger or smaller? Write a (+) or a (-) in the blank. **Problem 1:** 14 ___ 5 = 19 * Did 14 turn into a bigger or smaller number? * Sign: ___ **Problem 2:** 18 ___ 6 = 12 * Sign: ___ **Problem 3:** 8 ___ 8 = 16 * Sign: ___ **Problem 4:** 11 ___ 2 = 9 * Sign: ___ **Problem 5:** 20 ___ 0 = 20 * (Trick question! Both 20+0 and 20-0 equal 20! So either sign is right!) **Problem 6:** 7 ___ 5 = 12