Week 7TuesdayAdding 2-Digit Numbers
1Add Ones, Then Tens

Add the ones, then add the tens. Write the total.

23 + 45 =

34 + 54 =

42 + 36 =

53 + 24 =

2Estimate First!

Estimate First! About how much?

34 + 56

Round to tens: 30 + 50 = 80

About:

Actual:

61 + 28

Round to tens: 60 + 20 = 80

About:

Actual:

42 + 37

Round to tens: 40 + 30 = 70

About:

Actual:

3Step-by-Step Addition

Show your work: add ones, add tens, combine.

24 + 35

Ones: 4 + 5 =

Tens: 2 + 3 = 0

Total:

43 + 56

Ones: 3 + 6 =

Tens: 4 + 5 = 0

Total:

4Try Different Strategies

Use ANY strategy you prefer. Try a different one for each problem.

35 + 42 =

Strategy I used:

64 + 23 =

Strategy I used:

51 + 38 =

Strategy I used:

72 + 16 =

Strategy I used:

5Word Problems

Read carefully. Think about what is happening in the situation.

Sarah has 23 red marbles and 34 blue marbles. She wants to put them all in one jar. How many marbles will be in the jar?

Draw or write your thinking:

Answer: marbles

The library had 45 books on the top shelf and 32 books on the bottom shelf. A student wants to know the total books on both shelves. How many?

Draw or write your thinking:

Answer: books