🧠 Part 1: Mental Addition Practice

Strategy: Remove the zeros, add the smaller numbers mentally, then add the zeros back!

1. 4200 + 2700 = _________

Think: 42 + 27 = _____, then add back the zeros

2. 5300 + 2600 = _________

Think: 53 + 26 = _____, then scale by 100

3. 7100 + 1800 = _________

4. 6400 + 3500 = _________

5. 4800 + 3200 = _________

💭 Part 2: Show Your Thinking

6. Solve 6100 + 2500 using the mental strategy. Show each step:

Step 1: Remove zeros: _____ + _____ = _____

Step 2: Add zeros back: _____

7. Which mental strategy works best for adding 7300 + 1600?

Think 73 + 16, then add two zeros

Count on from 7300 by hundreds

Use a written method

Break into thousands and hundreds

8. Explain why the mental strategy of removing zeros works for these problems:

9. Create your own four-digit addition problem that can be solved mentally:

_______ + _______ = _______

Explain your mental strategy: