Lesson 5

Mass vs. Number

Est. Class Sessions: 3–4
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Mathematical Standards

3.OA.A
Represent and solve problems involving multiplication and division. (3.OA.A.3)
3.MD.A
Solve problems involving measurement and estimation. (3.MD.A.2)
3.MD.B
Represent and interpret data. (3.MD.B.4)

Standards for Mathematical Practice

MP1.
Make sense of problems and persevere in solving them.
MP2.
Reason quantitatively.
MP4.
Model with mathematics.
MP5.
Use appropriate tools strategically.
MP6.
Attend to precision.

Students investigate how the mass of nearly identical objects is related to the number of objects. They explore why measurements are not exact. They use patterns in their data to make predictions and solve problems involving multiplication.

Content in this Lesson

  • Measuring mass in grams [E6].
  • Using patterns in tables and graphs to make predictions and solve problems [E10, E11].
  • Representing the variables and procedures of an investigation in a drawing [E8].
  • Collecting and organizing data in a table [E7].
  • Making a point graph and drawing a best-fit line [E9].
  • Solving problems using multiplication and division [E3].
  • Dealing with precision and accuracy.
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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 of Student Groups

two-pan balance
set of standard masses (ten 1-gram masses, ten 5-gram masses, five 10-gram masses, and two 20-gram masses)
10 identical objects
small piece of clay (for leveling the balance)
ruler

Materials for the Teacher

Unit 12 Assessment Record
two-pan balance
set of standard masses (ten 1-gram masses, ten 5-gram masses, five 10-gram masses, and two 20-gram masses)
10 identical objects
small piece of clay (for leveling the balance)
ruler

Materials Preparation

Gather Items to Mass. Collect 10 identical objects for each student group to measure. The items should be as close to identical as possible. Each item should have a mass between 3 and 20 grams, such as pattern blocks, new pencils, marbles, or whole pieces of chalk. Gather a different set of the same object to demonstrate the lab.

Assessment in this Lesson

Assessment Expectation Assessed

Investigating Mass vs. Number
Check-In: Questions 1, 2, and 6
with Feedback Box
Student Activity Book
Pages 495–497, 500
E6.
Measure mass in grams.
E7.
Collect and organize data in a table.
E8.
Represent the variables and procedures of an investigation in a drawing.
E9.
Make a point graph using ordered pairs and draw a best-fit line.

Vocabulary in this Lesson