Math Investigations

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Chapter 13

Part 1: For the activity in the Teacher's Edition, page 352

Students can practice their research skills by looking at grocery store advertisements, or you can provide them with the data sheet that shows the price of some products from a grocery store advertisement found in the Activity Page (PDF file).

Have students bring in grocery store advertisements from newspapers. Make a bulletin board with two columns, one labeled Sold by the Pound and the other labeled Sold by the Quart. Tack the ads the students found in the appropriate column on the bulletin board.

Answers:

If you use the information we provided, the following items are sold by the quart or the pound.

Sold by the pound:
Bacon $3.49 a pound
Pork steaks $1.39 a pound
Asparagus $1.99 a pound
Strawberries $1.69 a pound
Ground beef $2.29 a pound
Apples $0.69 a pound
Cheddar cheese $4.99 a pound

Sold by the quart:
Milk $1.15 a quart
Whip cream $6.69 a quart
Orange juice $2.59 a quart

Part 2: Be an Investigator

A good time to do this investigation is after Lesson 6 on customary units of capacity.

Materials

  • measuring cups
  • containers of different sizes labeled A, B, and C (Note: choose containers whose measures are exact to the cup)
  • pails of water

Introducing the Investigation

Introduce the investigation by reading aloud the assignment at the top of the first page of the Description of Investigation and Student Report (PDF file), by having one of your students read aloud the assignment, or by having the students read the assignment individually.

You might want to set up a station for each container in the classroom. At each station, have a pail of water, a measuring cup, and one of the labeled containers. The students can move from station to station.

Put students in groups of two to four to work on the investigation.

Doing the Investigation

Ask students to talk about the methods they used for estimating. Ask students if they got better at estimating on the second and third containers.

Student Report

The Student Report gives students an opportunity to show and explain what they have done.

Extending the Investigation

Do the same kind of investigation with weight. Have the students estimate the weight of objects, weigh the object, and compare the estimate with the actual weight.


Houghton Mifflin Math Grade 3