Lesson 1

Multiplication and Rectangles

Est. Class Sessions: 2–3
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Mathematical Standards

4.NBT.B
Use place value understanding and properties of operations to perform multi-digit arithmetic. (4.NBT.B.5, 4.NBT.B.6)
4.OA.B
Gain familiarity with factors and multiples. (4.OA.B.4)

Standards for Mathematical Practice

MP1.
Make sense of problmes and persevere in solving them.
MP2.
Reason abstractly and quantitatively.
MP3.
Construct viable arguments and critique the reasoning of others.
MP8.
Look for and express regularity in repeated reasoning.

Students explore multiplication by investigating the dimensions of rectangular arrays. They then use their rectangles to investigate multiples, prime numbers, composite numbers, and square numbers. The use of exponents to write square numbers is introduced.

Content in this Lesson

  • Representing and solving multiplication problems using rectangular arrays [E1].
  • Determining whether one number is a multiple of another.
  • Finding all the factors of a number using rectangular arrays.
  • Identifying prime numbers [E4].
  • Identifying square numbers [E5].
  • Using the turn-around rule (commutative property of multiplication).
  • Using exponents to write square numbers.
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Materials for Students

Daily Practice and Problems Lesson Homework Assessment

Student Books

 Student Guide
Student Activity Book

Teacher Resources

 Teacher Guide - digital

Supplies for Student Groups

50 square-inch tiles per group (3–4 students)
tape
scissors
resealable plastic bag for storing tiles, optional

Materials for the Teacher

25 sheets of chart paper or construction paper for mounting rectangles on class chart, 1 for each number 1–25
Unit 3 Assessment Record

Materials Preparation

Small Multiplication Tables. Make copies of the Small Multiplication Tables Master and cut out the tables. Give each student a table to tape to his or her desk and one to take home. Students can refer to the tables as they work on this and future activities. In this way, students practice using the facts in many problem-solving situations and develop confidence that they have the tools they need to find solutions.

Square-Inch Tiles. Count out in advance 50 square-inch tiles per group of three to four students and place them in resealable bags.

TIMS Tip

During multiplication fact quizzes, students can cover the multiplication tables with a book.

Assessment in this Lesson

Assessment Expectation Assessed
Multiplication and Rectangles
 Check-In: Questions 17–18
Student Guide
Page 69
E1.
Represent and solve multiplication and division problems using rectangular arrays.
E4.
Identify prime numbers.
E5.
Identify square numbers.