MS After School Intervention Unit: Powers, Square Roots, & Order of Operations Day 4 Lesson Objective Students will solve problems using the order of operations. Common Core Standards: 6.EE.1 Write and evaluate numerical expressions involving whole-number exponents. Materials “Integer and Operation Cards” resource sheet (cut into square cards before start of the lesson) “Grab Bag Cards” resource sheet (one per pair, cut into square cards before start of the lesson) Grab bags (one per pair) Number cubes Document camera or overhead projector White boards and markers “Exit Ticket” resource sheet (one per student) “Traffic Lights” resource sheet (one half sheet per student) Warm-Up: The Tip Problem (15 minutes) Separate the class into two groups and read the following scenario: “Mark and his brother John are at a restaurant and are arguing over the tip. Mark wants to tip 20% on the total before taxes, but John wants to leave the 20% on the total after taxes. The bill total is $50, and taxes are an additional $2.50.” Have one group discuss Mark’s proposal and the other group discuss John’s proposal. Each group should come up with the tip cost, the total amount they will pay after tip, and the order of operations that will lead to their solution. (Solution: Mark’s method: tip is $10.00 and $62.50 is total with tip, John’s method: tip is $10.50 and $63.00 is total with tip.) Have each group present their answers. Have groups discuss which option is “more appropriate” and why. (Answers will vary.) Fill in the Operations (20 minutes) Separate the class into small groups. Open a set of integer and operation cards. Choose five integer cards and place them under the document camera or on the overhead, grouping four together and the last integer by itself. Explain that the students must use their operations and the first four integers in order to arrive at the fifth integer as their solution. For instance, place the integers 1, 2, 3 and 4 in a group with the result being 6. Students will arrange their own cards to set up the problem. A possible solution would be 2 4 1 3 6 . Discuss the solution and place it on the document camera or overhead. Explain that you are going to use the same integers and operations, but in a different order to arrive at the number 7 instead. The solution would be 2 (4 1) 3 7 . Discuss, as a class, how to represent adding 4 + 1 first. Use the integer and operation cards to go through a few more examples, while discussing order of operations. Moving with Math (20 minutes) Lead students through the Introductory Activity on page 14 of Moving with Math: Number Sense, Reasoning and Data (MH1). Students should practice moving from a statement to physical representation, to the symbolic representation with correct grouping symbols. Using the example from the Introductory Activity on page 15, have students explain how to group 2 5 4 to get a solution of 18. Have students explain why their method does not produce a solution of 14. Give additional examples from the exercises on the top of page 15, having students include grouping symbols to generate a desired solution. Make sure students explain their reasoning. Grab Bag (20 minutes) Assign each student a partner. Each set of partners should have a grab bag filled with the grab bag cards and a number cube. One partner should roll the number cube and pick three cards from the grab bag. The number on the cube represents the starting value, and the three operations from the grab bag are to be applied, in the order in which they are pulled. The partners should work out the problem on their paper, determining how to correctly write the problem with parentheses, exponents, etc. Once they have worked out the solution, the partners should write the problem on a white board and switch with another set of partners, who will evaluate the problem and explain the steps. Partners should continue to set up, switch, and solve problems until the time limit has been reached, replacing the grab bag cards as they go. Exit Ticket (10 minutes) Have students complete the exit ticket and turn in. Check for accuracy to see how well students mastered the lesson. Exit Ticket: Evaluate each problem. Show work and/or explain what you did to find the answer. 1. 32 5 (2 4) Solution: 8 2. 2 5 4 2 2 Solution: 11 3. 8 2 3 23 Solution: 10 4. 9 (5 2) 2 Solution: 0 5. 8 2 (4 1) 3 Solution: 1 Closure – Traffic Light (5 minutes) Hand each student a traffic light. Ask the following questions, and have the students point to green if they are “good to go,” yellow if they “need to slow” or red if they “need to stop and review.” 1. How do you feel about combining multiplication and division with addition and subtraction to evaluate a single problem? 2. How do you feel when you must evaluate a problem involving exponents? 3. How do you feel when you must evaluate a problem involving parentheses? 4. How do you feel about the order of operations overall? Integer and Operation Cards 1 2 3 4 5 6 7 8 9 10 + + – – ( ) = Grab Bag Cards Divide by 2 Add 3 Subtract 9 Multiply by 4 Raise to the second power Subtract 1 Add 8 Multiply by 2 Divide by 3 Raise to the third power Add 5 Subtract 7 Add 10 Subtract 4 Multiply by 5 Multiply by 10 Subtract 10 Add 12 Divide by 4 Add 1 Subtract 2 Exit Ticket Exit Ticket: Evaluate each problem. Show work and/or explain what you did to find the answer. 1. 32 5 (2 4) 2. 2 5 4 2 2 3. 8 2 3 23 4. 9 (5 2) 2 5. 8 2 (4 1) 3 Traffic Lights