K-5 friendly lesson

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

Use Compensation to Subtract (Without a Number Line)

🤔 Time to drop the number line drawing! See if you can "steal too much and give it back" entirely inside your brain.

Lesson 4

Concept

Compensation is the fastest way to do massive subtraction without grabbing a pencil and paper to regroup. 🎯 **Mental Math Steps:** **Problem: 53 - 18 = ?** 1. See the 18. Pretend it's 20. 2. 53 - 20 = 33. 3. 20 is exactly TWO more than 18. I stole 2 extra. 4. I must GIVE 2 BACK. 5. 33 + 2 = 35. Answer: 35.

Try it

Do it in your head! **Instructions:** Subtract a perfect ten, then add the extra back on! **Problem 1: 66 - 29 = ?** * See 29. Make it 30. * 66 - 30 = ___ * Add 1 back: ___ + 1 = ___ * Answer: ___ **Problem 2: 44 - 18 = ?** * See 18. Make it 20. * 44 - 20 = ___ * Add 2 back: ___ + 2 = ___ * Answer: ___ **Problem 3: 81 - 39 = ?** * Answer: ___ **Problem 4: 95 - 49 = ?** * Answer: ___