Lesson 1

Working with Groups

Est. Class Sessions: 2
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Mathematical Standards

2.OA.A
Represent and solve problems involving addition and subtraction. (2.OA.A.1)
2.OA.B
Add and subtract within 20. (2.OA.B.2)
2.OA.C
Work with equal groups of objects to gain foundations for multiplication. (2.OA.C.3, 2.OA.C.4)
2.G.A
Reason with shapes and their attributes. (2.G.A.2)

Standards for Mathematical Practice

MP2.
Reason quantitatively.
MP3.
Construct viable arguments and critique the reasoning of others.
MP6.
Attend to precision.
MP8.
Look for and express regularity in repeated reasoning.

Students are introduced to basic multiplication concepts. They place tiles in groups of 2, 3, 4, 5, and 6, write repeated addition number sentences, investigate the movements of constant math hoppers, and represent even numbers as the sum of two equal addends.

Content in this Lesson

  • Determining whether a group of objects has an odd or even number of members (e.g., by pairing objects or counting them by 2s) [E1].
  • Representing multiplication problems using tiles, drawings, number lines, and rectangular arrays [E2].
  • Writing a number sentence to express an even number as a sum of two equal addends [E6].
  • Solving multiplication problems using strategies (e.g., skip counting, repeated addition) with tiles, drawings, number lines, rectangular arrays, and number sentences [E7].
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Materials for Students

Daily Practice and Problems Lesson Homework Assessment

Student Books

 Student Activity Book

Teacher Resources

 Teacher Guide - digital

Supplies for Students

desk number line (0–100)
green triangle pattern block, optional

Supplies for Student Pairs

about 40 square-inch tiles

Materials for the Teacher

Display of Constant Math Hopper Number Line Assessment Master (Teacher Guide)
Unit 12 Assessment Record
Math Facts Class Record
chart paper
about 40 square-inch tiles
chalk, optional

Materials Preparation

Prepare Triangle Flash Cards. Prepare copies of the Triangle Flash Cards: Group D on heavier paper or card stock for each student. Have students cut apart each set and store them in an envelope or plastic bag. Provide each student with two sets, one to use at school and one to take home. Students will need these cards on an ongoing basis.

Prepare Chart for Even and Odd Numbers. Use chart paper to create a chart with the title “Number Sentences for Even and Odd Numbers.” Divide the chart into two columns: Even Numbers and Odd Numbers. You will use this chart in Part 2 to write number sentences for even and odd numbers.

Prepare Optional Targeted Practice. Make copies of the Constant Math Hopper Number Lines Assessment Master. Write different directions for each number line such as “Show 3 + 5 hops.” Copy these pages to make as much additional practice as needed.

Assessment in this Lesson

ASSESSMENT EXPECTATION ASSESSED
Equal Groups
Student Activity Book
Pages 593–594
E1.
Determine whether a group of objects has an odd or even number of members (e.g., by pairing objects or counting them by 2s).
E2.
Represent multiplication and division problems using tiles, drawings, number lines, rectangular arrays, and number sentences.
E6.
Write a number sentence to express an even number as a sum of two equal addends.
E7.
Solve multiplication and division problems using strategies (e.g., skip counting, repeated addition) with tiles, drawings, number lines, rectangular arrays, and number sentences.
DPP Item A
Triangle Flash Cards: Group D Subtraction Facts
Teacher Guide - digital
E9.
Demonstrate fluency with the subtraction facts related to the addition facts in Group D (6 − 3, 7 − 3, 7 − 4, 8 − 4, 9 − 4, 9 − 5, 12 − 6, 13 − 6, 13 − 7, 14 − 7, 15 − 7, 15 − 8, 16 − 8, 19 − 10, 19 − 9, 20 − 10).
DPP Item D
Subtraction Strategies
Teacher Guide - digital
E9.
Demonstrate fluency with the subtraction facts related to the addition facts in Group D (6 − 3, 7 − 3, 7 − 4, 8 − 4, 9 − 4, 9 − 5, 12 − 6, 13 − 6, 13 − 7, 14 − 7, 15 − 7, 15 − 8, 16 − 8, 19 − 10, 19 − 9, 20 − 10).

Vocabulary in this Lesson