UNIT X UNIT 8 | 317 B • Reinforce math vocabulary Use examples and classroom objects to help students understand fractions. For example, say: A ruler is 12 inches long. My desk is 48 inches long. The ruler is 1/ 4 the length of my desk. • Interpret data Read aloud the first item in Activity B. Think aloud to compare the two measurements. Say: I know that 1 whole is equal to 5/ 5. So, 11 5/ 5 is the same as 12. And 11 5/ 5 - 3 1/ 5 = 8 4/ 5 • Exchange information Once students have completed Activity B, ask volunteers to share their answers. Guide students to discuss and reconcile inconsistencies. ANSWERS 1. 8 4/ 5 2. 3 1/ 4 x 4 = 13 million light years 3. 180,000 x 1/ 2 = 90,000 light years in diameter C Make connections Provide students with an example of a fraction used in everyday life. Say: If I wanted to make pancakes, I would need 1/ 2 cup of water. What other fractions do you use in your life or at school? Have students work in groups to complete Activity C. ANSWERS Sample answers: 1/ 8 of a pizza is a slice of pizza. We use fractions to divide candy among a group of friends. The teachers use fractions to grade our papers (9/10 correct). Practice Book p. 172 Assessment Program p. 150 FORMATIVE ASSESSMENT DIFFERENTIATED INSTRUCTION Scaffold Help students develop their academic vocabulary around fractions by providing language frames. Then have students use the fractions and objects you have already recorded to say descriptive sentences about the fractions. Each student got ____ of the ____. The ___ was divided into ____ portions. The numerator in ____ is larger than the numerator in ____. Amplify Discuss the relationships between megaparsecs and light years on page 316. Have students revisit measurements in megaparsecs and convert them to measurements in light years. Then have students write complete sentences about what they discover. Write: Solve fraction word problems Write three fractions. Write one object you might measure with each fraction. PRACTICE COMMUNICATE B Fraction word problems Draw a picture and write an equation to solve each problem. 1. The galaxy Messier 81 is 31 5 Mpc away from the Milky Way. The Sombrero Galaxy is 12 Mpc away. How much farther is the Sombrero Galaxy from the Milky Way? 2. The galaxy Centaurus is about 4 Mpc away from the Milky Way. If 1 Mpc is about 31 4 million light years, how far away is the galaxy Centaurus? 3. The diameter of the Milky Way Galaxy is about 180,000 light years. The diameter of the galaxy Messier 81 is 1 2 the diameter of the Milky Way. What is the diameter of Messier 81? C Making connections What are some examples of situations in your life or at school that use fractions? Discuss your ideas as a group. Then, work together to write a fraction word problem. 317 UNIT 8 UNIT 8 / CONNECT TO MATHEMATICS
RkJQdWJsaXNoZXIy MjUyNzA0NQ==