Math in the World: Fractions and Decimals

Aim:                 How are fractions and decimals related?

Objective:         The students will be able to see how fractions relate to decimals by using hands-on/real-world examples.

Materials:         Dollar bills—real or fake (one for each group)

                        Candy

                        Small bags

Do Now:          Students will sit in groups of four.  Teacher will give each group a dollar.  Teacher will ask: What fraction of ten dollars does this dollar represent?

Procedure:        Teacher will explain:  A decimal is a number that uses place value and a decimal point in order to show amounts that are less than “1” as in tenths.  $0.20 is less than 1 dollar.  $0.20 is two-tenths of a dollar.  Two dimes will equal $0.20.

                        Teacher will explain that decimals are actually just another way of writing a fraction.  2/10 of a dollar is the same as $0.20.  Teacher will reinforce the “Math: It’s Everywhere!” concept by asking students, “Where do you see decimals used in the real world?” 

                        Possible answers: When you shop, you are buying items that are priced using decimals ($0.99 for a small Slurpee)

                        Serving Sizes on the back of chips and pretzels are often listed as “1.5 or 2.5.”

                        Teacher will ask ten students to come to the front of the room. 

                        What fraction of the students at the front of the room are girls?  Teacher will explain that if 7 of the students at the front of the room are girls (7/10) then this can also be expressed as 0.7. 

                        (Note: I have found that students enjoy this exercise immensely.  Who doesn’t want to get out of their seat and become a part of the math problem?  Consider repeating the exercise several times so that all of the students can volunteer and the concept is reinforced!)

Activity:            Teacher will provide small groups with a bag of 10 pieces of candy (candy should be made up of different kinds of candy, so that you can ask them to differentiate).  Each group will answer these questions (see worksheet below):

                        What fraction of the candy is chocolate? 

                        Can you express the amount of chocolate as a decimal?

                        What fraction of the candy is hard candy?

                        Can you express the amount of hard candy as a decimal?

                        What fraction of the candy does your group want to eat?

                        Can you express this amount as a decimal? 

Students can then create a bar graph to express the different kinds of candy in the bag.

Assessment:      Teacher assesses student’s understanding from oral questioning, as well as group answers and the bar graph.  The students will be asked to bring in a short paragraph explaining where they saw math in the world.

 See Worksheet: Click Here!

Sample Student Work (Click on the Thumbnail to enlarge the photo)

For more information, please contact April Paine at april_paine@hotmail.com