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Order of Operations Engage whole class and pairs Key Language Strategy Use Option 2 strategies Hear Math, See Math, Do Math, Write Math, and Talk Math, in the Teacher’s Edition, Differentiated Instruction, Small Group Options Language Objectives Activate Prior Knowledge Initiate a discussion about buying a number of items, such as school supplies. Ask students for suggestions of school supplies, such as notebooks, pencils, markers, rulers. Write suggestions on the board. Explain Hands-on Lesson Pose a school-supplies problem to the class. Say: Sari bought 5 pencils at $0.50 each and 2 notebooks at $1.10 each. How much did she spend? Explain that the best way to do a word problem is to turn each part of it into an algebraic expression. Say: We’ll use the letter p for the cost of a pencil and the letter n for the cost of a notebook. Sari spent 5p on pencils and 2n on notebooks. 5p and 2n are algebraic expressions. Write the expressions, equation, and solution on the board. ● Share and request information. ● Follow oral and written directions. 5p + 2n = Total Spent 5 × $0.50 = $2.50; 2 × $1.10 = $2.20 $2.50 + $2.20 = $4.70 ● Discuss when things are done in a certain order. For example, students wake up, get out of bed, and then brush their teeth. Explain the order of operations used in mathematics: do the operations in parentheses first; multiply and divide from left to right; then add and subtract. Model how to evaluate (7 × 6) + (5 × 4) using the order of operations to solve. (62) ● Distribute Learning Resource 24 and have pairs of fluent and nonfluent students solve using order of operations. (56) Math Objectives ● Evaluate expressions. ● Use the proper order of operations. Math Vocabulary algebraic expression, evaluate, order of operations Lesson Vocabulary baseball, box, calculator, football, parentheses Evaluate Assessment Check students’ mastery of division as they complete the lesson. See Assessment Checklist on page 101. Materials • crayons or markers • Learning Resource 24 Beginning Oral: Ask students to point to the expression. Writing: Ask them to write the symbols used in an expression. 94 Lesson 24 Intermediate Oral: Ask students to read the expression for the school-supplies problem aloud. Writing: Have students write the expression. Advanced Oral: Ask students to tell you the first order of operation. Writing: Have students write an expression using parentheses. 24 Name Order of Operations © Macmillan/McGraw-Hill Read the word problem below. Work with a partner to solve it. Mr. Johnson bought some new sports equipment for the school. He bought 7 boxes of baseballs and 4 boxes of footballs. Every box of baseballs holds 6. Two of the boxes of footballs hold 5 footballs and two other boxes hold 2. How many balls did Mr. Johnson buy in all? Look at the expression below to help you solve the problem. Fill in your answer in the blank. (7 6) (2 5) (2 2) boxes of baseballs boxes of footballs baseballs per box boxes of footballs footballs per box footballs per box Order of Operations 95