Adding Two-Digit Numbers Mentally

Solve the following addition problem: 2 + 3 = _____.

• 5

• 4

• 6

• 7

How many colorful kittens are there in all? Show how to find the sum by adding tens and ones. Write a number in each blank.

_______ tens + _______ ones = _______ colorful kittens

• 10 tens + 5 ones = 105 colorful kittens

• 5 tens + 10 ones = 60 colorful kittens

• 7 tens + 3 ones = 73 colorful kittens

• 8 tens + 2 ones = 82 colorful kittens

Ben wants to add 32 + 21 + 69 + 28. Which problems show a way Ben can find the sum. Circle all the correct answers.

• 60 + 90

• 3 + 2 + 6 + 2 + 30 + 20 + 60 + 20

• 30 + 20 + 60 + 20 + 2 + 1 + 9 + 8

• 122 + 28

Denny is adding these numbers. For which of these problems can Denny make a ten to help him find the sum?

• A. 26 + 12 + 24 + 73

• B. 39 + 64 + 45 + 51

• C. 35 + 37 + 52 + 64

• D. 44 + 91 + 27 + 20

The importance of using place value understanding to add two-digit numbers is:

• It helps in understanding the value of each digit.

• It makes addition faster.

• It is not important.

• It complicates the process.

How can strategies such as making a ten and breaking numbers into tens and ones be applied in addition?

• By simplifying the addition process

• By making the problem more complex

• By using multiplication instead

• By ignoring the tens and ones

Which of the following scenarios involves the addition of multiple two-digit numbers?

• Calculating the total cost of groceries with prices like $12, $23, and $34.

• Measuring the length of a room using a single measuring tape.

• Determining the area of a square with side length 15 cm.

• Finding the average temperature over a week with daily temperatures of 70°F, 72°F, and 68°F.

What are different methods for adding multi-digit numbers and how can you recognize equivalent expressions?

• Using the standard algorithm and recognizing patterns

• Using estimation and rounding

• Using visual models and number lines

• All of the above

Developing confidence and accuracy in performing multi-step addition problems can be achieved by:

• Practicing regularly and reviewing mistakes

• Avoiding practice to prevent errors

• Relying solely on a calculator

• Ignoring mistakes and moving on

1. Mentally Calculate Anna's Total Points : 43 + 28 + 26 = ?

• 97

• 98

• 99

• 100