Lesson 9 Add Three-digit Numbers
Let’s practice adding within 1,000.
Warm-up Number Talk: Ten and Some More
Find the value of each expression mentally.
Activity 1 How Did You Add Three-digit Numbers?
Find the value of each expression. Show your thinking.
Activity 2 Analyze and Add
Noah and Kiran showed how they found the value of
Noah’s work
Kiran’s work
How is Noah and Kiran’s work the same? How is it different?
Which student found the correct value? Explain or show your thinking.
Practice Problem
Problem 1
Here is how Jada found the value of
Explain Jada’s error.
Correct Jada’s work and find the value of
.