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21st Century Lessons Evaluating Expression Primary Lesson Designers: Kristie Conners Sean Moran 1 Warm Up OBJECTIVE: SWBAT evaluate algebraic expressions. Language Objective: SWBAT describe the steps to evaluating expressions. A magic store is selling exploding pens for $3 each plus $1 for tax. Kyle thinks you can figure out the cost of 10 pens with the below. 3 10 1 Do you agree or disagree? Explain. Click to reveal next part Agenda 7 Agenda: OBJECTIVE: SWBAT evaluate algebraic expressions. Language Objective: SWBAT describe the steps to evaluating expressions. 1) Warm Up 2) Launch Individual Shopping with Marvin- Whole Class/Pairs 3) Explore- 1 Evaluating with Marvin- Whole Class 4) Explore- 2 Practice with Formulas- Whole Class Class work: Can’t Wait to Evaluate – Groups 5) Practice 6) Assessment Exit Slip- Individual 8 Launch- Shopping with Marvin Marvin the Math Magician has a problem for you. He wants to buy some magic wands and some magician hats. The wands cost $8 each and $5 for each hat. How much will Marvin have to pay for 12 wands and 7 hats? Agenda 9 Launch- Shopping with Marvin How did you get your answer? The wands cost $8 each and $5 for each hat. How much will Marvin have to pay for 12 wands and 7 hats? How can we write a to show our answer of 131? 8 12 5 7 Click to reveal next part Agenda 10 Explore 1- Evaluating with Marvin How much will Marvin have to pay for 6 wands and 3 hats? Write an numerical expression to find the answer. Remember: the wands cost $8 each and $5 for each hat. 8 6 5 3 48 15 63 Click to reveal next part Agenda 11 Explore 1- Evaluating with Marvin 8 12 5 7 8 6 5 3 12 wands 7 hats The wands cost $8 each and $5 for each hat. 6 wands 3 hats What changed in the two examples? Sometimes it helps to represent a problem as an w= # of wands h= # of hats Click to reveal next part Agenda 12 Explore 1- Evaluating with Marvin How much will Marvin have to pay for 10 wands and 2 hats? w = 10 h = 2 8w 5h w 5 h 8 10 2 80 10 90 This is called substitution!! We just evaluated the expression. Click to reveal next part 13 evaluate Agenda Explore 1- Evaluating with Marvin Find the cost of buying 9 wands and 7 hats. w= 9 h= 7 15 8w 5h h 9 5 7 8 w 72 35 107 Steps: 1. Copy the expression. 2. Substitute the value in for the variable. 3. Evaluate using the order of operations. Click to reveal next part Agenda Explore 2- Formulas Flashback… Objective: evaluate algebraic expressions. We can use the process of evaluating to solve problems in the real world. For example: engineers, architects and builders use geometric formulas every day. Circumference C d Volume Rectangular Prism V lwh Surface Area Cylinder SA 2 r dh 2 Click to reveal next part Agenda 16 Explore 2- Formulas Volume is the amount of space a shape takes up. The expression for calculating the volume of the rectangular prism is below. 5ft or lwh l w h Find the volume l w h Steps: 1. Copy the expression. 36 5 3 180 ft 2. Substitute the value in for the variable. 3. Evaluate using the order of operations. Click to reveal next part Agenda 17 Explore 2- Formulas Surface Area is the total of the area of all sides. The expression for calculating the surface area of a rectangular prism is below. 5ft 2lw 2lh 2wh Find the volume. 2lw 2lh 2wh 2 2 2 72 90 40 2 202 ft 18 Steps: 1. Copy the expression. 2. Substitute the value in for the variable. 3. Evaluate using the order of operations. Click to reveal next part Agenda Practice- Class work Can’t Wait To Evaluate! Directions: Each group receives a set of Evaluation Cards along with two different colored number cubes. Before starting, the team decides which color cube stands for which variable. (Example: the red cube replaces a, the green cube replaces b.) One person in the group rolls the number cubes. Students use the numbers to evaluate the expression. a=____ 3a 2b ab ab 2 a b 2b 5 b ab 2( ab ) 2 3a 1 aa 19 b=____ 3( a b ) a 4b a b Agenda Summary Can’t Wait To Evaluate! Click each problem for demonstration a=____ 3a 2b ab ab 2 a b 2b 5 b ab 2( ab ) 2 3a 1 aa 20 b=____ 3( a b ) a 4b a b Agenda Exit Slip Kiara was asked to evaluate the expression 27 p . Her answer was 14. Did she substitute 11, 13, or 15? How do you know? Answer : 13 27 – 13 14 Agenda 32