# 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

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?

## 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?

## 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?

## 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?

## Activity 2 Missing Numbers

Lin’s brother spilled water on her math work!

Figure out what number Lin wrote before it got smudged.

Lin wrote a one-digit number with which you

*can*make a new ten when you find the value of the sum.What could Lin’s number be?

Write equations to show your thinking.Lin wrote a one-digit number with which you

*can not*make a new ten when you find the value of the sum.What could Lin’s number be?

Write equations to show your thinking.Lin wrote a two-digit number with which you

*can*make a new ten when you find the value of the sum.What could Lin’s number be?

Write equations to show your thinking.Lin wrote a two-digit number with which you

*can not*make a new ten when you find the value of the sum.What could Lin’s number be?

Write equations to show your thinking.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.

How are the problems the same?

How are they different?