
Subjects

Grades 35, 68, 912 
Brief Description
Students estimate and average phone listings found in the White Pages of the local telephone directory.
Objectives
Students will
Keywords
telephone, directory, alphabet, estimate, average, chart, table
Materials Needed[shopmaterials]
Lesson Plan
Lesson Notes:
 This math activity is designed to be done by hand, but students might use a spreadsheet program to organize and calculate data.
 If you live in a large, urban area, you might figure the total of listings for a handful of specific letters rather than for the entire phone book.
Pose this question to students: How many listings can be found in the White Pages of the local phone directory? Let students consider how they might figure that out. Help them conclude that it would be very difficult to accurately count the listings by hand; however estimating might help them arrive at a number close to the actual number.
Invite students to share their ideas about how they might estimate the number of White Pages listings. Lead them to the conclusion that the easiest way to estimate is to count the number of listings in one column on a page, then add or multiply the number of listings in one column by the number of columns on the page.
Students can use the number of listings on a page (estimated) to figure the total listings for that letter. They can do that by counting the number of pages for a specific letter and multiplying the number of listings on a page by the number of pages.
Tear a sheet of paper into 25 slips. Write a letter of the alphabet on each slip. Omit one letter, for example the letter V. Use that letter as an example as you walk students through the activity. Put the slips in a hat, and let students randomly draw three letters. Students should record the three letters and put the slips back into the hat so the next student can select. Do this until all students have selected three letters. Then write the chart headings below on the board or chart paper:
Assigned Letter  Actual Number of Listings in One Column  Estimated Number of Listings on One Page  Actual Number of Pages for Letter  Approximate Number of Listings for Letter 

Which letter of the alphabet did you omit when you wrote out the slips in the step above? If it was the letter V, model the exercise students will do using the phone listings in your local phone directory that begin with the letter V.
Older students can provide more detail in the last two columns. For example, they might write 17 pages, two extra columns. in the "Actual Number of Pages for Letter" column. To find a total number of listings for the letter in the last column, they can multiply the number of listings on a page (p) by 17, then add the number of listings in a column (c) two times [(p x 17) + (c x 2) = ] to arrive at the total number of listings.
Distribute the Let Your Fingers Do the Estimating student work sheet, and ask students to complete the work sheet for the three letters they drew.
After the students have completed that activity, bring the class together so students who had the same letters can compare their estimates. Did students who drew the letter A come close to one another in their estimates? If the estimates are far apart, let those students share how they arrived at their estimates. Otherwise, write the different estimates on the board or chart paper and let students figure the average. That average will serve as the official class estimate of the number of listings for the letter A.
Do the same thing for the other letters of the alphabet. As you do that, students can record the official class estimates on their work sheets in each of the three columns after each letter.
When students have determined all the estimates, give them time to total the estimates. (This might be a homework assignment.) They should add the estimates once; then they should add them again in reverse. If they arrive at two different answers when figuring the total, they should total the column again to see if that third total matches the total in one of the other columns.
Assessment
Students write a brief paragraph explaining the math processes they used to figure the total number of listings in the White Pages of the local phone book. Invite a handful of students to share what they wrote, and then help them improve on their explanations. Then give all students the opportunity to turn in their explanations for a grade or the opportunity to rework/improve their explanations as homework and turn the revised work in for a grade.
Lesson Plan Source
Education World
Submitted By
Gary Hopkins
National Standards
LANGUAGE ARTS: English
MATHEMATICS: Number and Operations
MATHEMATICS: Problem Solving
MATHEMATICS: Communications
MATHEMATICS: Connections
TECHNOLOGY
Return to Phone Book Math.
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