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32 females----------------------------------------------------

3 males

Getting Reading for Algebra by Using Virtual Manipulatives “Using Ratios, Proportions, and Percents”

Adapted from Connected Mathematics©1998 by Michigan State University, Lappan, G., Fey, J., Fitzgerald, W., Friel, S., and Phillips, E.

SREB Readiness Indicator Addressed: Write and use ratios, rates, and proportions to describe situations and solve problems (SREB Indicator #4).

Activity Rationale: Mastering proportions, ratios, and percents and the connections among them is essential for algebra and beyond. Similarity, slope, and scale are just a few of the many math topics that require numerical fluency in these areas. This activity provides practice in setting up and solving problems with missing values involving ratios, proportions, and percents.

In this activity, you will compare representations of ratios and percents using the online tool, Percentages, for grades 6-8. The tool is located at the National Library of Virtual Manipulatives.

Experience It!A ratio is a comparison of two quantities that tells the scale between them. Ratios can be expressed as quotients, fractions, decimals, percents, or in the form of a:b.

Here are some examples:The ratio of girls to boys on the swim team is 2:3 or

A percent is a part of a whole expressed in hundredths. For example ½ can be expressed as 50/100, or 50 percent (%).

1. Go to http://matti.usu.edu/nlvm/nav/grade_g_3.html.

2. Choose Percentages.

© 2000-2006 Education Development Center, Inc., through its project, EdTech Leaders® Online, http://www.edtechleaders.org . All rights reserved.

3. Use the tool and the given information to answer the questions below.

A homeroom class of 32 students at Springbrook Middle School completed a survey about the food they eat. Each student was asked to list any foods that he or she liked to eat. The results for five different foods are listed in the table below:

Food Female MaleChips 14 13Hamburgers 7 13Apples 10 9Oranges 16 12Spinach 4 1Total Surveyed 17 15

Example: What percentage of females liked chips?Fraction Percentage

Part 14 14 82%Whole 17 17

To display the percent and pie chart for this relationship using the Percentages applet, enter the Whole and Part information into the corresponding boxes, then click Compute.

a. What percentage of males liked chips?Fill in the chart to show how the problem should be set up.

Fraction PercentagePartWhole

© 2000-2006 Education Development Center, Inc., through its project, EdTech Leaders® Online, http://www.edtechleaders.org . All rights reserved. 2

b. What percentage of the class liked chips? Fill in the chart to show how the problem should be set up.

Fraction PercentagePartWhole

c. What percentage of the class liked spinach? Fill in the chart to show how the problem should be set up.

Fraction PercentagePartWhole

d. Explain whether a higher percentage of males or females liked apples. Fill in the chart to show how the problem should be set up.

Females Fraction PercentagePartWholeMales Fraction PercentagePartWhole

e. If 57 % of the males liked hot dogs, how many males said they liked hot dogs? Fill in the chart to show how the problem should be set up.

Fraction PercentagePartWholeExplain if this is possible or not and why.

f. Given that the tool computes the missing value for the student, what benefit does the tool provide? What skills does it reinforce? What skills are not reinforced by the tool? Under what circumstances would you use this tool?

© 2000-2006 Education Development Center, Inc., through its project, EdTech Leaders® Online, http://www.edtechleaders.org . All rights reserved. 3