# A Lesson on Subtraction that uses area codes

Subject:

Math

4, 5

Gelin Rice

Topic: Arithmetic: Subtraction

Name of Activity: Area Code Math

Materials Needed:

Telephone Book

U.S. Map with area codes on it

Description of Activity:

The phone book’s listing of area codes provides a novel source of three digit subtraction, addition, and multiplication practice as well as promotes map – reading skills and knowledge of U.S. geography.

Prepare a map of the United States with the area codes on it. Use the telephone book’s area – code map as a model. Also prepare a set of math problems based on the area codes such as:

Eastern North Carolina plus Colorado equals?

Northern Minnesota times Arizona equals?

Students will use their maps to find the numbers indicated by state and area names and will perform the operations specified More sophisticated word problems can be based on area code information such as:

If Mark in Cincinnati wants to talk to Rachel ion Chicago, what state’s area code

must he add to his own to get the right area code for Chicago?

What city s area code multiplied by 2 will give you the area code for

Independence, MO?

Reference: Great Ideas: From Learning Volume One Math.

PA: Springhouse Corporation. p. 21. Idea by: Carol Lauritzen, Kansas City, MO.

(1986). Springhouse