In this lesson, students will add three-digit numbers using expanded form addition and standard algorithm addition. They'll explain their answers and highlight the steps for each of the strategies.
Students will be able to use two addition strategies to add three-digit numbers.
The adjustment to the whole group lesson is a modification to differentiate for children who are English learners.
EL adjustments
Introduction
(5 minutes)
Display the example box from the Three-Digit Addition: Part 1 worksheet and ask students to turn and talk to their partners about what they see and notice about the mathematical problem and solution strategies.
Ask students to share some of their impressions about the problem (e.g., they decompose the numbers to add more simple numbers, there are two strategies to solve the same problem, expanded notation takes up more space, etc.).
Tell students that today they'll learn how to use the two strategies to solve addition problems.
Beginning
Have students look at one solution strategy at a time.
Allow students to point to the parts of the solution they notice and support students as they learn necessary vocabulary.
Intermediate
Review the definition of "strategy." Activate background knowledge by having students tell you about a math strategy they've used in the past.
Support students to analyze the solution methods by using the following sentence stem: "I notice ________."