Ratios and Proportions

Mamie P. Scott Edward Coles Elementary School
8440 South Phillips
Chicago, Il. 60617


The seventh grade student will:

Review ratios and proportions.

Determine the relationship between individual height and reach.

Find equal ratios.

Solve word problems using ratios by trial and error.

Practice finding pictorial expressions of fractions to
decode a message.


Measuring tapes or string
Chart paper
Construction paper (red, to make 15 Red beans; white, to make
15 Black-eyed peas; and green, to make 15
Lima beans)
Worksheet with pictorial expressions of fractions

Recommended Strategies:

. Form small groups of three or four students.
. Distribute measuring tape or string to each group.
. Use the tape or string to measure and compare height to reach.
. Record results on chart paper in this order:
________________________________________________________________ Tall-Rectangle Perfect-Square Short-Rectangle If the height > reach, record name under "tall-rectangle" If the height < reach, record name under "short-rectangle" If the height = reach, record name under "perfect-square" . Students whose names are in the "Perfect-Square" column will be the Chef Cook to make the "Three Bean Salads" for the first activity. . Distribute beans randomly (one per student). . Write salad recipe on the chalkboard. . Call a Chef Cook to read and make the first salad by selecting beans (students) from any group. Each salad contains Red beans, Lima beans and Black-eyed peas #1 This salad contains: 4 Red beans 1/2 as many Black-eyed peas as Red beans 10 beans in all #2 This salad contains: 2 Lima beans Twice as many Red beans as Lima beans 10 beans in all #3 This salad contains: An equal number of Red beans and Black-eyed peas 5 more Lima beans than Red beans No more than 20 beans . Groups should be encouraged to make up 3 different salads and continue the activity. . Next, distribute worksheet to each student with fraction message: Students will solve problems, analyze which of the coded solutions would best fit and, by substitution of the lettered answer, be able to decode the message. . Discuss the message. References:

Burns, Marilyn. The I Hate Mathematics Book. Boston, Mass.:
Little, Brown, and Company, 1975.

National Council of Teachers of Mathematics, Fraction Message.
Arithmetic Teacher 36 (December 1988): 32.

Stenmark, Jean Kerr, Thompson, Virginia, and Cossey, Ruth.
Family Math. Berkley, Calif.: Lawrence Hall of Science, 1986.

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