Return to Mathematics IndexMultiplication and Areas

Albert Michael Robert Fulton Elementary School

5300 S. Hermitage

Chicago IL 60609

(312) 535-9000Objectives (Grades 3-5):

To learn two-digit multiplication using math facts.

To find areas of rectangles and squares.

To review addition and subtraction facts.

To be able to fill an order of items of equal and different prices and

quantities.Materials Needed:

rulers, stamps (new and/or used, singles and sheets of different denominations

and sizes), magazine ads stamps (from the Ed McMahon $10,000,000 Sweepstakes),

stamp order catalogues, play money (dollars and change), transparent grids and

Lego platforms with different numbers of squares and dots, scissors, order formsStrategies:

Show the students 3x4, 4x5, 6x4 square grids, or various sizes of Lego platforms

and ask them to count the squares and the dots one at a time. Next, show them

large size grids and Lego platforms and have them count the dots individually.

Tell them to count the number of squares or dots in one row across and another

row down and multiply the two numbers. Point out that it is much easier and

faster to count the total by this method. Demonstrate this on the board.

Distribute 3x3, 4x3, and 4x4 sheets of stamps. Ask the students to find the

total area of each sheet and then find how much each sheet costs. Ask how much

would you pay if each sheet costs 4 times the face value. Have one student

from each group be the stamp dealer from whom the children can buy stamps.

Pass out sheets of different denominations, sizes, and quantities. Ask the

students to find the area of one stamp and then the area of the whole sheet.

Next, find the total price of each sheet.

Distribute single, square stamps, preferably used, each attached to a piece of

cardboard paper for easy manipulation and protection from being mutilated. Find

the area of each stamp and then determine how many stamps would fit in an area

of 24x24 sq. cm., 28x28 sq. cm., and 35x35 sq. cm., for example. You may want

to reverse all activities to look like this one.

Here is anexamplefor another activity:

Suppose you spilled some liquid on one of the sheets that you treasure very much

and you are willing to pay any reasonable price to replace it. The sheet has

40 stamps of 22 cents each. The dealer asks for an extra 15 cents per stamp

over the face value. Find out how much you would pay per stamp, then for the

sheet. Also calculate the profit the dealer made.

Distribute sheets of different quantities. Ask students to find the face value

of each sheet by multiplying the price of one stamp by the number of stamps in

the sheets. Look for current prices in the catalogues and decide how much each

sheet would cost today. Next, find the area for one stamp and then for the

whole sheet.Notes: All the above activities may be used for the fifth grade for teaching

division. First, ask to find the area of the whole sheet and then the area of a

single stamp.

The same activities may be used to teach social studies. Ask questions about

the event or person the commemorative stamp was issued for.Performance Assessment:

Pass out the sheets of magazine ads stamps. Choose a denomination and write it

down on the lower right hand of each stamp. Find the area for one stamp and

then for the whole sheet. A dealer offers you 68% of the face value. Calculate

your loss if you decide to sell.

Pass out copies of order forms and ask them to order as many sheets or single

stamps as they want and write them in the proper columns in the form. Find out

the total of the order. Add sales tax and shipping and handling charges.

Write on the board the years in which the rate of first class mail went up in

one column, and the rate increase in another at random. Ask students to arrange

them chronologically. Next, ask them to make a line or a bar graph to show the

rate hike. Then have them calculate the percentage of the increase each time it

occurred.