Display the class number line (0–130) where students can see and reach it with a pointer.
Attach a desk number line (0–100) to each student's desk to use throughout the year.
Display the Math Practices page where all students can see it.
Gather two identical jars. See Materials Preparation in Lesson 1.
Gather about 200 small identical objects (e.g., paper clips, cubes, tiles). See Materials Preparation in Lesson 1.
Have the following tools readily available for the Daily Practice and Problems items in this unit.
- You and your students will need:
Triangle Flash Cards: Group E
(Teacher Guide)
Addition Facts I Know chart from Unit 1 Lesson 4 (Teacher Guide)
200 Chart (Student Activity Book) Reference
Addition Strategies Menu (Student Activity Book) Reference
metersticks
individual clocks
20 connecting cubes
number lines
coin jars and coins from Unit 1 Lesson 1
base-ten pieces
a collection of coins (pennies, nickels, dimes, and quarters)
| LESSON | SESSIONS | DESCRIPTION | SUPPLIES |
|---|---|---|---|
LESSON 1Estimation Strategies |
2 | In Part 1, students practice estimating the number of objects in a group using a sample or benchmark collection, and by identifying ”could be” and ”crazy” estimates. In Part 2, students estimate the total cost of two items using computational estimation. Students assess both the reasonableness of their estimates and of their answers by comparing the two. |
|
LESSON 2An Addition Seminar |
2–3 | Students develop strategies for solving addition problems with two-digit numbers. As a class, students share strategies and record them on a chart. |
|
LESSON 3The Nameless Scribe |
1–2 | A young girl has difficulty writing a three-digit number because she uses too many zeros. The girl exclaims in frustration that she would like to know who invented zero. Her mother tells a story that might resemble how zero was actually invented. |
|
LESSON 4Exploring with Base-Ten Pieces |
2 | Students explore addition of 2- and 3-digit numbers using their knowledge of place value. The lesson focuses on estimating answers for addition problems, using base-ten pieces to model the problem, and making trades of base-ten pieces if necessary. Students record their work using base-ten shorthand and symbols. |
|
LESSON 5Two Paper-and-Pencil Methods |
2 | In this lesson, students are introduced to two paper-and-pencil methods for adding two-digit numbers—the expanded form and the all-partials methods. Both methods build on the main idea that was introduced in Lesson 4, that each digit represents a number of tens or a number of ones. |
|
LESSON 6Making Connections |
2–3 | Students make connections between a variety of mental math and paper-and-pencil strategies as they solve two-digit and three-digit addition problems. They practice using the expanded form and all-partials methods, and are introduced to the compact method. |
|
LESSON 7Workshop: Addition Strategies |
2–3 | Students practice a variety of mental math and paper-and-pencil addition methods with two- and three-digit numbers. They estimate and check for reasonableness, and explore the efficiency and usefulness of the strategies in various situations. |
|
LESSON 8Snack Shop Addition |
2 | Students solve addition word problems using different methods such as expanded form, all-partials, and mental math, and different tools. They make estimations and check the reasonableness of their answers. They learn that a calculator is one of many tools available for checking answers and solving problems. |
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