Lesson 8

Multiplication at the Zoo

Est. Class Sessions: 2
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Mathematical Standards

4.NBT.A
Generalize place value understanding for multi-digit whole numbers. (4.NBT.A.2)
4.NBT.B
Use place value understanding and properties of operations to perform multi-digit arithmetic.(4.NBT.B.5)

Standards for Mathematical Practice

MP1.
Make sense of problems and persevere in solving them.
MP2.
Reason quantitatively.
MP3.
Construct viable arguments and critique the reasoning of others.
MP5.
Use appropriate tools strategically.
MP6.
Attend to precision.
MP7.
Look for and make use of structure.

Students solve multiplication story problems using their own mental math strategies. They also use expanded form and rectangular arrays to multiply one-digit by two-digit problems. These paper-and-pencil methods provide a conceptual foundation for more efficient procedures. Students then decide whether to estimate or find an exact answer, and then whether to use paper and pencil or mental math.

Content in this Lesson

  • Solving multiplication problems using invented strategies, mental math, and expanded form [E5].
  • Multiplying 2-digit numbers by 1-digit numbers using paper-and-pencil methods (expanded form and rectangular arrays) [E8].
  • Choosing appropriately from among mental math and paper-and-pencil methods to multiply whole numbers [E10].
  • Identifying the information in a problem [MPE1].
  • Describing solution strategies clearly [MPE5].
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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

Materials for the Teacher

When Do We Estimate? Master (from Lesson 6 Teacher Guide)
Unit 4 Assessment Record
Math Facts Class Record
chart paper

Materials Preparation

Digit Cards. If you have not done so already, make a set of Digit Cards 0–9 using index cards, a deck of playing cards or the Digit Cards 0–9 Masters. If using playing cards, the ace can stand for 1 and a face or joker card can stand for zero. These cards will be used to play a game in DPP item AA.

Multiplication Tables. Students should have their multiplication tables available. Students may use the Small Multiplication Tables distributed in Unit 3 Lesson 1 (also available as a Master in this unit) or their Multiplication Facts I Know charts from Unit 3 Lesson 2.

Assessment in this Lesson

Assessment Expectation Assessed Math Practice Assessed
Multiplication at the Zoo
Check-In:
Questions 14–15
Student Guide
Page 157 and corresponding Feedback Box
Teacher Guide - digital
E5.
Solve multiplication problems using mental math strategies (e.g., composing and decomposing numbers and doubling and halving).
E8.
Multiply 2-digit numbers by 1-digit numbers using paper-and-pencil methods (expanded form, all-partials, compact).
E10.
Choose appropriately between mental math and paper-and-pencil methods to multiply whole numbers.
MPE1.
Know the problem. I read the problem carefully. I know the questions to answer and what information is important.
MPE5.
Show my work. I show or tell how I arrived at my answer so someone else can understand my thinking.
DPP Item CC
Quiz on 2s and 3s
Teacher Guide - digital
E12.
Demonstrate fluency with the multiplication facts for the 2s, 3s, and 9s.