Lesson 4 Add and Subtract Three-digit Numbers in Different Ways
Let’s add and subtract three-digit numbers.
Warm-up Number Talk: Count Back by Place
Find the value of each expression mentally.
Activity 1 Zero Tens and Zero Ones
Mai and Lin were asked to find the value of
Here is their work.
Mai’s Work:
Lin’s Work:
Find the value of each expression.
Show your thinking.
Try Mai’s way to find
. Try Lin’s way to find
.
Activity 2 Add or Subtract with Expanded Form
Andre and Diego showed their thinking with equations to find the value of
. Andre’s Work
Diego’s Work
What is the same or different about their work?
Discuss with your partner.Try Andre’s way to find the value of
. Try Diego’s way to find the value of
. Choose your own way to find the value of
. Show your thinking. Choose your own way to find the value of
. Show your thinking.
Practice Problem
Problem 1
Find the value of
. Show your thinking. Find the value of
. Show your thinking.