Multiplicative Comparisons at the Giant's Door

Learning Resource Type

Learning Activity

Overview

In this resource from Bridges in Mathematics, students use a picture of a giant's doorway to solve multiplicative comparison problems.  They have to write an equation and find the answer using appropriate units.  A challenge problem includes a fractional scale factor.

Phase

After/Explain/Elaborate
Mathematics (2019) Grade(s): 4

MA19.4.1

Interpret and write equations for multiplicative comparisons.

UP:MA19.4.1

Vocabulary

  • Multiplicative comparison
  • Multiplier
  • Equation
  • Times as many
  • Times as much
  • Verbal statement
  • Factor
  • Product
  • Quantity
  • Multiple
  • Scale factor

Knowledge

Students know:
  • How to write an equation to represent a word situation.
  • Which quantity is being multiplied and which factor is telling how many times.
  • Varied language that describes multiplicative comparisons.

Skills

Students are able to:
  • Interpret equations for multiplicative comparisons.
  • Write equations for multiplicative comparisons.

Understanding

Students understand that:
  • Multiplicative comparisons relate the size of two quantities and a scale factor.
  • Factors in multiplication problems have different roles from each other in the context of comparison problems.
  • Explanations and drawings show ways multiplicative comparisons are similar to and different from equal groups and arrays.
Mathematics (2019) Grade(s): 4

MA19.4.2

Solve word problems involving multiplicative comparison using drawings and write equations to represent the problem, using a symbol for the unknown number.

UP:MA19.4.2

Vocabulary

  • Multiplicative comparison
  • Times as many
  • Product
  • Factor
  • Multiplication
  • Equation
  • Symbol
  • Additive comparison
  • Tape diagram
  • Unknown

Knowledge

Students know:
  • how to find products and quotients.
  • Recognize situations represented by multiplicative comparison.
  • Distinguish between multiplicative comparison and additive comparison.

Skills

Students are able to:
  • Solve word problems involving multiplicative comparison.
  • Write equations using a symbol for the unknown to represent word problems involving multiplicative comparison.
  • Use drawings to represent the word situation involving multiplicative comparison.

Understanding

Students understand that:
  • additive comparison focuses on the difference between two quantities and multiplicative comparison focuses on one quantity being some number times larger than another.

Learning Objectives

Students will be able to interpret and write equations for multiplicative comparisons.

Students will be able to solve word problems involving multiplicative comparison using drawings and write equations to represent the problem.

Activity Details

  • Display a copy of the worksheet before handing it out to the students.  Show the image and ask students what they see or notice. Identify all of the tools to make sure students are familiar with the items.
  • Read the directions, pointing out that the giant's hammer is 48" tall.  They will need to use that information to solve the problems.
  • Pass out the worksheet and give students time to work independently.  Walk around and make sure students are following the directions; help students as needed.
  • Collect the worksheet.  Review by having students share their strategies for solving the problems.

Assessment Strategies

Assess student work to determine if they were able to:

  • interpret and write equations for multiplicative comparisons.

  • solve word problems involving multiplicative comparison using drawings and write equations to represent the problem.

Variation Tips

This activity could be done with peer support or as a whole class.

The size of the hammer could be adjusted for easier calculations.

Background / Preparation

Preview the worksheet and prepare a way to display the image.

Make a copy of the worksheet for each student.

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