2.NBT.6 Add up to four two-digit numbers using strategies based on place value strategies and properties of operations.

Mental Math Warm-Up

Add 34 + 51

• Be prepared to share your strategy for how you solved it.

Math Strategies

36 + 22+ 12

Which two numbers would you add first?

Math Strategies

56 + 12 + 9

Which two numbers would you add first ?

4 two-digit addition

45 + 32 + 23 + 15

Which two numbers would you add first?

4 two-digit addition

Add

37

23

18

14

MP 3 Critique the Reasoning of Others

• My cousin Linda solved an addition problem. Does Linda have the correct answer?

• 57 + 42 + 24 + 11 = 135