Lesson 7 Does it Make a New Ten?

    • Let’s add one-digit and two-digit numbers and write equations.

Warm-up Which One Doesn’t Belong: Expressions

Which one doesn’t belong?

Activity 1 A Ten or Not a Ten?

Problem 1

Student with a thought cloud. Yes or no, question mark.

Jada likes to look for ways to make a new ten when she adds.
Would she be able to a make a new ten when she adds to find the value of this sum?

  1. If Jada could make a new ten, circle “Yes.”
    If Jada could not make a new ten, circle “No.”

    1. Yes

    2. No

  2. Explain how you know.
    Find the value.
    Write equations to show how you found the value of the sum.

Problem 2

Jada likes to look for ways to make a new ten when she adds.
Would she be able to a make a new ten when she adds to find the value of this sum?
Does the expression make a new ten?

  1. If Jada could make a new ten, circle “Yes.”
    If Jada could not make a new ten, circle “No.”

    1. Yes

    2. No

  2. Explain how you know.
    Find the value.
    Write equations to show how you found the value of the sum.

Problem 3

Jada likes to look for ways to make a new ten when she adds.
Would she be able to a make a new ten when she adds to find the value of this sum?
Does the expression make a new ten?

  1. If Jada could make a new ten, circle “Yes.”
    If Jada could not make a new ten, circle “No.”

    1. Yes

    2. No

  2. Explain how you know.
    Find the value.
    Write equations to show how you found the value of the sum.

Problem 4

Jada likes to look for ways to make a new ten when she adds.
Would she be able to a make a new ten when she adds to find the value of this sum?
Does the expression make a new ten?

  1. If Jada could make a new ten, circle “Yes.”
    If Jada could not make a new ten, circle “No.”

    1. Yes

    2. No

  2. Explain how you know.
    Find the value.
    Write equations to show how you found the value of the sum.

Activity 2 Missing Numbers

Lin’s brother spilled water on her math work!
Figure out what number Lin wrote before it got smudged.

  1. Lin wrote a one-digit number with which you can make a new ten when you find the value of the sum.

    Expression. 32 plus water mark.

    What could Lin’s number be?
    Write equations to show your thinking.

  2. Lin wrote a one-digit number with which you can not make a new ten when you find the value of the sum.

    Expression. 16 plus water mark.

    What could Lin’s number be?
    Write equations to show your thinking.

  3. Lin wrote a two-digit number with which you can make a new ten when you find the value of the sum.

    Expression. 8 plus water mark.

    What could Lin’s number be?
    Write equations to show your thinking.

  4. Lin wrote a two-digit number with which you can not make a new ten when you find the value of the sum.

    Expression. 8 plus water mark.

    What could Lin’s number be?
    Write equations to show your thinking.

  5. How do you know whether or not you can make a new ten when you are finding the value of a sum?

Practice Problem

Problem 1

Find the value of each sum.
Show your thinking using drawings, numbers, or words.

  3. How are the problems the same?
    How are they different?