Use the Eggsactly Eggs overhead to review fractions as part of a set of 12.
For example, ask students how to show 1/2 of a dozen. Accept equivalent fractions (6/12, 3/6, etc.) and all the arrangements of six eggs in a carton that holds twelve eggs.
For the main lesson, students will investigate how their fractions would change if the egg carton holds 18 eggs instead of 12. Have students remove varying numbers of eggs to represent a fraction of the carton that remains. Students should also be given the fraction and asked to model using 18 eggs. The 18 Eggs in a Carton activity sheet should be used as students discover the different representations for each of the fractions.
Ask students how many eggs are in the set. [18.] Suppose nine are used to bake a cake. Have students remove nine eggs. Students should record their egg configuration on the activity sheet. Have students participate in a gallery walk examining other students’ egg cartons to see all the different ways students might have removed nine.
- Ask students what all the egg cartons have in common. [There are nine remaining.]
- What fraction of the entire set is nine? [9/18; accept 1/2 or other equivalent fractions. If students do not make the connection between equivalent fractions, e.g., 9/18 = 1/2, they will have an opportunity to develop these relationships in the next lesson.]
- What fraction was removed? [9/18 or 1/2.] Have students label their recording sheet as 9/18. [Some students may choose to label their sheet with an equivalent fraction such as 3/6. This provides an excellent opportunity to work with equivalent fractions.]
Continue removing varying numbers of eggs. For example, suppose this time that we need twelve eggs to bake our cake. Have students remove twelve eggs. Students should record their egg configuration on the 18 Eggs in a Carton activity sheet. Have students go on another gallery walk to see all the different ways students might have removed twelve.
- Ask students what all the egg cartons have in common. [There are six remaining.]
- What fraction of the entire set is twelve? [12/18; accept 2/3 or 4/6.]
- What fraction was removed? [6/18 or 1/3 or 2/6.] Have students label their recording sheet as directed by the activity sheet.
Have students investigate the different ways they can arrange their eggs when given the fraction. For example, ask students to show 1/3 of eighteen eggs. (Use the 18 Eggs in a Carton activity sheet to have students represent several different configurations all equivalent to 1/3 of eighteen eggs.)
Have students work in pairs to continue the investigation as different numbers of eggs are used. Students should be given time to investigate the variety of ways in which the eggs can be arranged. These arrangements should be recorded on the and the sheet should be labeled according to the fraction. For example, students might use several pictures of egg cartons on the 18 Eggs in a Carton activity sheet to record all the ways to show 1/3 of eighteen eggs.
Identify fraction relationships associated with the set (e.g., 1/2 of the set of 18 eggs is the same as 9/18 of the set, OR when the numerator stays the same and the denominator increases, the fractions become smaller — 1/3 is smaller in area than 1/2).
