Estimating – Phone Book Math

How many phone numbers are listed in your local white pages?  No, don’t start counting!  Use estimation.

Use a ruler to measure the column of names and numbers.  Divide by two.  Draw a line under the name that is found when you measure one-half of the name column.

Now count the names that appear in the first half of the first column of names.  Multiply that number by four.  Call your answer x.

Next use subtraction to determine how many pages of listing are in the white pages.  Call the results y.

Multiply again (x times y) to reach your estimate!

Younger learners can choose one letter of the alphabet to estimate.  Advanced learners can calculate each letter individually and make a graph.