COMPANION WEBSITE ACTIVITY Quarters, Quarts, and More Quarters: A Fraction Unit Level: 3-6 Setting: individual, small group, and whole group 1 Objective: Students recognize and represent the fraction 4 in common and decimal forms from their experiences. Materials: quarters, grid paper, fraction circles, manila paper This unit focuses on activities that deal with the concepts of one-quarter and twenty-five hundredths. The activities build on children’s present knowledge to review and extend their understanding of the many areas of their lives in which the concepts appear. When the unit is concluded, children will have reinforced their understanding of one-quarter as one of four equal parts of a whole and the numerals 14 and 0.25 as numerals for these parts. Session 1: How Are Quarters Used? Begin by asking, “How many settings can you think of in which the idea of one-quarter is used? I want you to write a sentence in which you tell one way in which you have recently used quarter, one-quarter of, twenty-five hundredths, or any other word or words that mean the same as these terms.” Examples of responses given by children in one class include: • “My mother gave me a quarter for each window I washed.” • “At the end of the first quarter, our team had a 7-to-3 lead.” • Set up learning stations, such as one for linear measure that has foot and metric rulers, yard- and metersticks, and measuring tapes in metric units and inches. Create similar stations with devices for measuring weight, capacity, and time. • Have children work in cooperative groups, one or two groups at each station. They are to study the measuring devices to determine ways in which one-quarter is associated with them. One student in each group should make a list of the group’s findings. In some instances they list devices or measurements that are a quarter of a unit, such as “a 14 -teaspoon measuring spoon,” “a 14 -cup mark on a measuring cup,” and “a quarter-yard mark on a yardstick.” In other instances, the quarter must be determined by the children. They might indicate such things as “15 minutes is a quarter of an hour,” “3 inches are a quarter of a foot,” “4 ounces is a quarter of a pound,” “25 centimeters is 0.25 of a meter,” and “250 grams is 0.25 of a kilogram.” Allow time for each group to work at two stations. • Discuss the items on each list. Students should be ready to demonstrate the accuracy of each item on their lists. Session 3: Pattern Blocks Materials: Pattern blocks • “I used a quarter of a cup of butter when I made a batch of vanilla cookies.” • Provide each student with a handful of pattern-block pieces, including at least four green triangle pieces and these instructions: “Make a design in which green triangles are one-quarter of the design’s area. Draw a copy of your design; color the green part(s) of your design. Write a statement in which you explain how you know that green is one-quarter of your design.” • “Twenty-five cents is twenty-five hundredths of a dollar and is called a ‘quarter.’” • The drawings and explanations can become part of the bulletin board begun in the first session. • “I ate a quarter of the pizza my family had for dinner last night.” • “A quart of milk is one-quarter of a gallon.” • “The sale sign said one-quarter off all merchandise on the table.” • “I live about one-quarter mile from school.” • “This line is twenty-five hundredths of a meter long.” When the children have finished, have them share their sentences. As the discussion proceeds, categorize the ways in which quarters is used. Categories might include distance or length, money, time, and capacity. The nature and variety of children’s responses give clues about their understanding of common and decimal fractions. Responses within a narrow range of uses are an indication that the children have a limited understanding of the concepts involved. A connection between mathematics and art can be made by having the children make pictures to portray their uses of quarter. These drawings will make up part of a bulletin board display they will make during the course of the unit. Session 2: Quarters and Measurement Materials: Measuring devices, such as rulers and tape measures; small- and large-capacity containers; scales; clocks and stopwatches that measure seconds. Devices should measure in both metric and English units. Session 4: Equivalent Common and Decimal Fractions Materials: Fraction strips, geometric fraction models, base-10 materials • Each child will have a set of fraction strips, geometric models, or base-10 materials. Children with fraction strips or geometric models begin by locating a one-quarter piece; children with base-10 materials show 0.25 with their materials. • During this activity, children use their models and imaginations to determine as many common fractions that are equivalent to 14 or decimal fractions that are equivalent to 0.25 as they can. (Children working with decimal models must have the content and pedagogical readiness necessary to visualize how hundredths can be subdivided to show thousandths, ten-thousandths, and so on. Refrain from telling them that 0.25 can be changed to 0.250 by affixing a zero.) Courtesy of Safe-T Classroom Products, Inc. • After each child has identified a number of equivalent common or decimal fractions, ask: “Does anyone have a common fraction with a denominator larger than 32?” Have children who have such denominators write their equivalent common fractions on the chalkboard or on an overhead projector transparency. Order the common fractions, with largest denominator on the left and smallest on the right. Fill in any gaps so that there is a complete sequence of equivalent common fractions from largest to 14 . Children can verify equivalencies with calculators capable of working with common fractions, using the simplification function on their machines. Pattern block • Children who used base-10 materials should be asked to list their decimal fractions. It will become evident that the decimal fractions 0.25, 0.250, 0.2500, and so on are all equivalent. Session 5: A Visit to Paula Porter’s Pizza Parlor • Begin with this story: “Paula Porter is ready to open her new pizza parlor. Paula’s is going to be different from other pizza parlors because her pizzas will have a rectangular shape. She will conduct a contest in which customers will cut a pizza into four equal-size pieces in imaginative ways. The patron whose pizza is judged the most imaginative will be given a free pizza each month for a year. Each person in the contest gets to eat the pizza she or he cuts.” • Follow the story with these instructions: “You are going to practice for Paula’s contest. Use paper from your notepad to represent Paula’s pizzas. Decide what you think is the most imaginative way to cut the pizza into four equal-size pieces. You will be limited to five tries, so think about how you will make your cuts before you do any cutting. Remember: Equal-size does not mean that each of the four pieces has to have the same shape as the other pieces. Be ready to explain how you know that your pizza is cut into four equivalent-size pieces.” • Have students add their “pizzas” to the bulletin board display. Allow time for them to study the pizzas before they vote for the one that is cut in the most imaginative way. Discussion of the different cuts will enrich children’s understanding of the many ways one-fourth can be represented. “Most imaginative” is subjective. Point out that all shapes that meet the criterion of showing a pizza cut into four equal-size pieces are really winners. (When items are removed from the bulletin board, children can put them in their mathematics folders.) • If possible, arrange with the school’s food service to have pizza for lunch on the day of this activity.
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