UNIT X 316 | UNIT 8 Instructional Routine: Mathematics p. Txxxii Solve Fraction Word Problems A • Build academic vocabulary Use the vocabulary routine to present or reinforce the words, megaparsec, light year, numerator, denominator, and fraction. • Listen actively Play the audio and direct students to listen closely for the new words as they follow along. Then replay the audio to build comprehension of the content. • Identify the problem Reread the explanatory text (up to the question: How much farther is the Pinwheel Galaxy from the Milky Way?) aloud while students follow along. Have students raise their hands if they hear unfamiliar vocabulary or if they do not understand anything as you read. Reread the question. Explain to students that the most important step in solving word problems is to identify the problem. Call on volunteers to read the next questions and call on other students to read the answers in color. • Use fractions to solve word problems Tell students to look at the number line and describe it. Point out three points on the number line: Milky Way, Andromeda, and Pinwheel. Say: We live in the Milky Way Galaxy. Other galaxies are so far away, we measure the distance in megaparsecs. Essential Question: How can you use fractions to solve word problems? Use academic language Read aloud the Essential Question and elicit answers. Have students explain how drawing pictures can help illustrate fractions and help solve word problems. ANSWERS Sample answer: We can measure by first finding the lowest common denominator (LCD) between the two fractions. Then we write an equation to represent the problem and solve. EXPLORE AND LEARN DIFFERENTIATED INSTRUCTION Scaffold Fractions can be challenging for students to work with if they do not have concrete examples. Remind students how to convert unlike fractions. Say: For unlike fractions, we must first find the lowest common denominator (LCD). The lowest common denominator for 4/ 5 and 3/ 4 is 20. 4/ 5 : We multiplied the denominator by 4, so we must also multiply the numerator by 4. The converted fraction is 16/ 20. 3/ 4 : We multiplied the denominator by 5, so we must also multiply the numerator by 5. The converted fraction is 15/ 20. Amplify Give students the tools and opportunity to take measurements of their heights. Have students write their heights in feet, using fractions to represent the inches. For example, a student who is 50 inches tall would write 4 1/ 6 ft. Then have pairs write equations using their measurements to find the difference in height between them. the Milky Way Galaxy the Andromeda Galaxy A Read the informational text. Solve Fraction Word Problems Explorers are often sent to uncharted regions to find answers to mysteries about our world and beyond. Missions to outer space have searched for answers about the planets in our solar system, our galaxy, and the universe. Our galaxy, the Milky Way, is one of many galaxies in the universe. The distances between galaxies are so large that they are measured in megaparsecs (Mpc). One megaparsec is about 31 4 million light years. Let’s try a fraction word problem about the galaxy. The Andromeda Galaxy is 3 4 Mpc from the Milky Way. The Pinwheel Galaxy is 34 5 Mpc from the Milky Way. How much farther is the Pinwheel Galaxy from the Milky Way? • What is the problem about? the distances between two galaxies and the Milky Way the Andromeda Galaxy is 3 4 Mpc from the Milky Way the Pinwheel Galaxy is 34 5 Mpc from the Milky Way • What are we trying to find? how much farther the Pinwheel Galaxy is from the Milky Way • Draw a picture of the problem. • Write an equation to represent the problem and solve. 34 5 − 3 4 = 3 16 20 − 15 20 = 3 1 20 • Write a sentence containing your answer. The Pinwheel Galaxy is 3 1 20 Mpc farther from the Milky Way than the Andromeda Galaxy. Solve Fraction Word Problems How can you use fractions to solve word problems? ? ESSENTIAL QUESTION 0 1 2 3 3 4 Milky Way Galaxy Andromeda Galaxy Pinwheel Galaxy 3 4 4 5 ? 316 CONNECT TO Mathematics UNIT 8 UNIT 8 / CONNECT TO MATHEMATICS
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