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 and organize sets of base-ten pieces (21 bits, 20 skinnies, and 3–5 flats).
Have the following tools readily available for the Daily Practice and Problems items in this unit.
- You and your students will need:
Addition Flash Cards: Group A
(Teacher Guide)
200 Chart (Student Activity Book) Reference
Addition Strategies Menu (Student Activity Book) Reference
Subtraction Strategies Menu (Student Activity Book) Reference
base-ten pieces
individual clocks
number lines
centimeter/inch rulers
coin jars and coins from Unit 1 Lesson 1
a collection of coins (pennies, nickels, dimes, and quarters)
- You will also need:
class number line (0–130)
demonstration clock
| LESSON | SESSIONS | DESCRIPTION | SUPPLIES |
|---|---|---|---|
LESSON 1Strategies for Subtraction Facts |
2–3 | Students revisit the Subtraction Strategies Menu for the Facts to discuss which strategies seem to be better suited for different subtraction facts. Students then focus on using the Triangle Flash Cards to practice subtraction facts related to the addition facts in Group A. |
|
LESSON 2Subtraction Seminar |
2–3 | Students develop strategies for solving subtraction problems with two- and three-digit numbers. Students share strategies, record them on a chart, and practice using the strategies to solve problems. |
|
LESSON 3Is It Reasonable |
1–2 | Students practice estimation skills, focusing on whether an answer makes sense. They estimate the answers to problems and explain how they determined their estimates. |
|
LESSON 4Subtraction with Base-Ten Pieces |
2 | Students partition a number in different ways while solving subtraction problems with base-ten pieces. This helps them develop a concrete understanding of the trading involved in subtraction in preparation for their work with paper-and-pencil algorithms. |
|
LESSON 5Paper-and-Pencil Subtraction: Expanded Form |
2–3 | Students are introduced to the expanded form paper-and-pencil method to solve multidigit subtraction problems with some regrouping. They make connections between base-ten pieces and expanded form. They practice checking their subtraction with addition. |
|
LESSON 6Paper-and-Pencil Subtraction: Compact Method |
2–3 | In this lesson, students solve subtraction problems using paper and pencil. They begin by recording their work with base-ten pieces on base-ten recording sheets. Then they use a standard paper-and-pencil subtraction algorithm, the compact method, to solve problems. They check their work with addition. |
|
LESSON 7Make Connection with Subtraction |
2 | Students make connections between a variety of mental math and paper-and-pencil strategies as they solve multidigit subtraction problems. They solve problems using invented strategies, base-ten pieces, expanded form, and the compact method. |
|
LESSON 8Workshop: Subtraction Practice |
2 | Students practice a variety of mental math and paper-and-pencil subtraction methods with multidigit numbers. They estimate and check for reasonableness, and explore the efficiency and usefulness of the strategies in various situations. |
|
LESSON 9Snack Shop Addition and Subtraction |
1–2 | Students solve addition and subtraction problems based on the Shooting Star Snack Shop Children’s Menu that was introduced in Unit 7. Students calculate total snack shop bills and determine the amount of change or the amount of additional money needed. |
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