Algebra 1 Concept Lesson – Unit 2 Making the Team – Getting Started LESSON OVERVIEW Overview: This is a two-part lesson, with informal exploration in Part 1, followed by more formal mathematical work in Part 2. In Part 1, students first explore the situation by creating a table that shows at least ten possible pairs of Long and Freestyle Dance scores, then each student in the group plots her/his ten points (S,L) on a group graph. Students then use the given formula to calculate Total scores for each of their combinations of scores on the Short and Long Programs and add the total scores to their tables. They identify the points on the graph that represent combinations that qualify for the team, and those combinations that produce a total score of exactly 60 points. They then look for patterns in their group graphs and generate initial conclusions about the situation. This is followed by a class discussion in which selected groups present their results. All of the transparencies with group graphs are superimposed on each other on the overhead to form a single class graph. Groups then look for patterns in the class graph and use it to evaluate their group’s thinking and make additional conjectures. Part 2 begins with each small group writing the inequality that describes conditions for “making the team”. Students then decide how to shade their graph to indicate the region that contains points that “make the team”. They then use their equation or graph to answer a series of questions about the situation and interpret specific points on the graph in terms of the problem situation. Next, they describe what each of the regions of the graph represent—the region containing points that are circled, and the region containing points that aren’t circled. They also identify the meaning of the points that are starred. Finally, they use their graph to answer the “Key Questions”. TX Standards Addressed: §111.32. Mathematics, Algebra I (A.7) Linear functions. The student formulates equations and inequalities based on linear functions, uses a variety of methods to solve them, and analyzes the solutions in terms of the situation. The student is expected to: (A) analyze situations involving linear functions and formulate linear equations or inequalities to solve problems; (B) investigate methods for solving linear equations and inequalities using concrete models, graphs, and the properties of equality, select a method, and solve the equations and inequalities; and (C) interpret and determine the reasonableness of solutions to linear equations and inequalities Mathematical Goals of the Lesson: Begin to develop an understanding of inequalities in the coordinate plane and their use in representing mathematical situations and solving problems. Begin to develop an understanding of the relationship between inequalities and their graphs. Write inequalities to describe specific conditions in a situation. Evaluate algebraic expressions in two variables and interpret the results in terms of a mathematical situation. Begin to develop the ability to solve linear inequalities graphically. Interpret regions of the graph of linear inequalities in terms of the mathematical situation and identify the solution region for a particular problem. Reason and solve problems using graphs and equations. Reason mathematically and use and make connections among a variety of mathematical representations. LEARNING RESEARCH AND DEVELOPMENT CENTER © 2007 University of Pittsburgh Funded by the James Irvine Foundation Academic Language Goals of the Lesson: Develop academic vocabulary to be used in the descriptions. Describe the conditions in a situation algebraically, orally or in writing. Explain the process used in solving the task, orally or in writing. Assumption of Prior Knowledge: Solving linear equations in one variable Experience graphing inequalities in one variable Experience graphing linear equations and use them to represent situations Identify and interpret key characteristics of graphs of linear equations, i.e., x- and y- intercepts Academic Language: Maximum and Minimum Inequality Intercepts Regions, solution regions, and boundary lines Materials: Task Calculators One transparency graph for each group, with axis and scale labeled (blackline master provided) A black overhead marker for each group Scores table (blackline master provided) Connections to the LAUSD Algebra 1, Unit 2, Instructional Guide Understand and graph linear equations in one and two variables using a variety of techniques LEARNING RESEARCH AND DEVELOPMENT CENTER Sketch the region defined by a linear inequality © 2007 University of Pittsburgh Funded by the James Irvine Foundation 2 Key: Suggested teacher questions are shown in bold print. Questions and strategies that support ELLs are underlined and identified by an asterisk. Possible student responses are shown in italics Phase S E T SET-UP PHASE: Setting Up the Mathematical Task INTRODUCING THE TASK Ask students whether they have either watched or been involved in competitions that involved multiple performances, U P such as skating, diving, cheerleading tryouts, play tryouts, etc. Ask them to describe how they think the different performances are used to determine a single final score. Listen for different types of combinations: those involving taking a simple average, i.e., weighing each component equally, and those involving weighted averages, i.e., some components are more important than others. Ask a student to read Part 1 of the task out loud as others follow along. Ask several students to explain what they are being asked to do in their own words*. Specifically ask, “What does this formula mean?” (The Freestyle Dance counts less than the Prepared Dance when you figure the total score; The Freestyle Dance is worth 40% of the total score; the Prepared Dance is worth 60% of the total score.) Clarify any confusions students may have, but do not suggest a method for solving the problems. Ask for any words or terms that the students do not understand. Clarify the meanings so that the task will be accessible to all students*. To assist ELLs’ participation in the class discussion*: Allow time for students to talk first in small groups (pairs) and then have the groups report to the whole class. Reinforce appropriate language as students communicate their ideas (e.g., revoice a student’s contribution in complete, grammatically correct language). Ask students if you have captured what they said. LEARNING RESEARCH AND DEVELOPMENT CENTER © 2007 University of Pittsburgh Funded by the James Irvine Foundation 3 EXPLORE PHASE: Supporting Students’ Exploration of the Task STRUCTURE Phase E X P L O R E E X P L O R E E X P L O R E PRIVATE THINK TIME Ask students to work individually for about 10 minutes so that they can make sense of the problem for themselves. Each student should create an individual table of values with at least 10 entries. Provide them with a blank table to use. Circulate around the classroom and clarify confusions. Be careful NOT to give away too much information or suggest a way to solve the problem. SMALL-GROUP WORK After about 10 minutes, ask students to work with their partner or in their small groups to construct their group graph on the transparent graph you provided. Each student should plot the points from his or her table on the graph. Students should then calculate the total score for each set of points, and enter this total into their table. They then should each circle or star the points that show combinations that give qualifying Total scores (60 or greater). As students are working, circulate around the room. o Be persistent in asking questions related to the mathematical ideas, problem-solving strategies, and connections between representations. o Be persistent in asking students to explain their thinking and reasoning. o Be persistent in asking students to explain, in their own words, what other students have said. o Be persistent in asking students to use appropriate mathematical language. What do I do if students have difficulty getting started? Ask: “What is a possible Freestyle Dance score?” “Prepared Dance score?” “How can you figure out the Total score that you get from those two scores?” “Does this Total score qualify for the team?” What do I do if students finish early? Look at students’ graphs and be sure they have plotted a sufficient number of points to (1) represent the full range of outcomes for the situation and (2) make the boundary line 60=.4X + .6Y visible on the graph. If not, prompt students to find combinations that minimally qualify for the team (i.e., where T=60). Ask a “quiet” group member to explain the work of the group. If s/he can’t explain, challenge the group to make sure that that group member understands, leave, and return later to ask again. MONITORING STUDENTS’ RESPONSES As you circulate, attend to students’ mathematical thinking and to the strategies and representations used, in order to identify those responses that will be shared during the Part 1 Share, Discuss, and Analyze Phase. During this phase, groups will (1) present their group graphs and (2) describe how they generated the table values that appear on the graph. For this task, you will need to: o Identify a graph to be used to begin the Share Phase. Look for a graph based on tables that were primarily generated unsystematically, i.e., simply selecting various combinations of Short and Prepared Dance scores. o Identify graphs based on tables with more systematic generation of combinations, e.g., containing multiple combinations for a single Freestyle Dance score, using extreme values (e.g., 0 or 100) as scores, etc. o Identify graphs based on tables in which students solved the equation 60= .4F + .6P to determine Prepared Dance scores that would produce a qualifying Total score for particular Freestyle Dance scores. o Identify graphs in which the boundary lines 60= .4F + .6P and/or S=60 are visible. LEARNING RESEARCH AND DEVELOPMENT CENTER © 2007 University of Pittsburgh Funded by the James Irvine Foundation 4 Phase Task Question: 1. Make a table that shows possible performance on the Short and Long Programs. Include at least 10 entries in your table. 2. Use a Black Marker to plot your possible performances (S, L) on your group graph. The x-axis represents the Freestyle Dance score (F) and the y-axis represents the Prepared Dance score (L). Possible Solutions E X P L O R E E X P L O R E E X P L O R E Look for indictors of students’ understanding: that the Freestyle and Prepared Dance scores are independent of each other, i.e., a given score on one can be associated with multiple scores on the other. of a systematic organized way of charting information. of a procedure for plotting points on a graph Possible Questions Ask questions such as: How did you generate the different combinations? What do the 0 and the 100 mean? (or 100 and 0?) Explain in your own words what (___) said (another student).* Misconceptions/ Errors Not realizing that Confusing the xand y-ax Making a Table: F P 100 0 60 60 70 60 60 90 60 70 90 80 LEARNING RESEARCH AND DEVELOPMENT CENTER © 2007 University of Pittsburgh Could someone else have the same Freestyle Dance score but a different Prepared Dance score (or vice versa)? Indicate one of the points. Ask, “How can we find the Freestyle Dance score that corresponds with this point? What is the Prepared Dance score that corresponds with the point?” the Short and Prepared Dance scores are independent of each other. Many combinations could be generated. 0 100 60 50 40 80 100 40 50 50 10 40 0 Questions to Address Misconceptions/Errors Funded by the James Irvine Foundation 5 Phase E X P L O R E E X P L O R E E X P L O R E Task Question: 3. A skater’s Freestyle Dance score (F) and Prepared Dance score (P) are combined to give the Total Score (T) using this formula: .4F + .6P = T Add a Total Score column to your table. Determine the total score for each of your entries and add these scores to your table. Possible Solutions Possible Questions Look for indictors of students’ understanding: of the Total score being a combination of the Freestyle and Prepared Dance scores using the indicated formula. Ask questions such as: How did you calculate a Total Score? Many combinations can be generated. The table below shows some key combinations, including those on the boundary line 60=.4F + .6P Making a Table: F P 0 100 60 50 40 80 100 40 50 50 10 40 0 100 0 60 60 70 60 60 90 60 70 90 80 Explain in your own words what ( __) said (another student).* Misconceptions/Errors Not realizing that the formula means that the Total adds together 40% of the Freestyle Dance score and 60% of the Prepared Dance score. Questions to Address Misconceptions/Errors Can a skater receive 200 points if s/he dances two perfect programs? What does .4F mean? What does .6P mean? A skater has a Freestyle T Having difficulty using 60 40 60 56 58 68 76 70 56 62 58 64 LEARNING RESEARCH AND DEVELOPMENT CENTER Dance score of 50 and a Prepared Dance score of 70. Explain how to find the Total score. the calculator to compute the total (make sure you try the students’ calculators so that you know how to perform this calculation on the model they will be using). © 2007 University of Pittsburgh Funded by the James Irvine Foundation What operation is indicated here? (.4F) Will you multiply first or add first? Have you asked your group mates to explain how to evaluate this expression? 6 Phase Task question: 4. To make the team, the skater’s Total score must be at least 60 points. a. CIRCLE the points that show combinations of scores that give Total scores that qualify for the team. b. Put a STAR on those points where the Total score is exactly 60. 5. Examine your graphs. What patterns do you notice? Discuss your answers with your team members. Explain how you arrived at your responses. What conclusions can you draw? Possible Solutions E X P L O R E Look for students who: have graphs that clearly show the boundary and/or regions, i.e., have sufficient numbers of points in each region so the pattern in the location of circled and non-circled points are visible. clearly articulate the boundary conditions, i.e., .4F +.6P =60, S=60. have interesting patterns/observations for the class to discuss. Possible Questions You might ask: How did you decide to circle these points? Why aren’t these points circled? Were there any points for which you had a hard time deciding whether to star them or not? Misconceptions/Errors If groups have not plotted enough points in the 2 regions or on the boundary line, they may not be able to readily see the mathematical connections in the graph. Questions to Address Misconceptions/Errors Ask groups to find and plot points: where .4F + .6P = 60 where .4F + .6P 60 where .4F + .6P 60 What patterns do you notice? E X P L O R E LEARNING RESEARCH AND DEVELOPMENT CENTER © 2007 University of Pittsburgh Funded by the James Irvine Foundation 7 Sharing, Discussing, and Analyzing Part 1 of the Task Orchestrating the mathematical discussion: a possible Sequence for sharing student work, Key Questions to achieve the goals of the lesson, and possible Student Responses that demonstrate understanding. The purpose of this sharing/discussion is to share approaches to the task, but most importantly, to combine the individual group graphs into a class graph that will contain more points, and thus make patterns in the graph more visible. Phase Sequencing of Student Work S H A R E Each group describes their strategy for completing the table and then displays their graph. Collect the graph after it is displayed to include in the class graph. D I S C U S S Order of group presentations: Graph based on tables: 1. Primarily generated unsystematically, i.e., simply selecting various combinations of Short and Prepared Dance scores. A N D A N A L Y Z E 2. With more systematic generation of combinations, e.g., containing multiple combinations for a single Freestyle Dance score, using extreme values (e.g., 0 or 100) as scores, etc. 3. Graphs based on tables in which students solved the equation 60= .4F + .6P to determine Prepared Dance scores that would produce a qualifying Total score for particular Freestyle Dance scores. Rationale and Mathematical Ideas This discussion will lay the foundation for the key ideas of graphing systems of inequalities: Boundary lines Regions Solution region The following key mathematical ideas may also surface that you can expand upon later, if you chose: Weighted average. Independent vs. dependent variables (this situation involves two independent variables, unlike most of the situations students have encountered so far. Discrete versus continuous representations. Graphs that represent just the problem situation (0< P<100) and (0<F<100) vs. the complete graphs F, P IR without limits. Possible Questions and Student Responses How did you select the values in your table? How did you generate the total scores? I just kept selecting pairs of numbers. I wanted to have a pattern in my table so I went up by 10’s. I first tried minimum and maximum values, e.g., 0 and 100, for the Short and Prepared Dance scores. After I calculated the Total scores for the points I had, I saw that none of my points would make the team, so I tried higher Short and Prepared Dance scores to see if the Total scores would make the team. I picked a Freestyle Dance score, and then used the formula to figure out what Prepared Dance score the person would have to get to qualify for the team. I set T=60, put in the value for S, then solved the equation for L. How did you decide whether to circle a point? How did you decide if it should be starred? I checked to see if the Total was greater than or equal to 60. What patterns or conclusions did you reach by looking at your graph? I noticed that all the points with stars are on a line. (Probe—to remind students that the points with stars indicate where T=60.) I noticed that the stars formed a slanty line that went downhill (Probe – does this line have a positive slope or a negative slope?). I noticed that all the points that are circled are above a slanty line. (Probe—to get to “above the line where T=60.) 4. Graphs in which the boundary line 60= .4F + .6P is visible. LEARNING RESEARCH AND DEVELOPMENT CENTER © 2007 University of Pittsburgh Funded by the James Irvine Foundation 8 Phase S H A R E D I S C U S S Sequencing of Student Work Rationale and Mathematical Ideas CLASS GRAPH This is a crucial phase of the lesson. By superimposing 4 or 5 of the group graphs, After the group the two regions and boundary line should presentations, collect be much more prominent, the stray points the transparencies with can be discussed, the patterns can be the group graphs from 4 discussed, and student understanding of or 5 groups and create a the mathematics in the context of the “superimposed Class situation reinforced. Graph” to display on the overhead. Possible Questions and Student Responses Look at the class graph. How does it compare to your group graph? What patterns do you see in the class graph? Do they support or contradict what you noticed in your group graph? Why? Because there are more points, the boundary lines are more visible. Now we can see two 2 different regions in the graph, one where the points are circled and the other where the points are not circled. A N D A N A L Y Z E LEARNING RESEARCH AND DEVELOPMENT CENTER © 2007 University of Pittsburgh Funded by the James Irvine Foundation 9 Part 2: Be sure to return each group’s graph. They will add to it in this part of the lesson. Phase Task question: What condition has to be true for a skater to make the team? Write the inequality that represents this condition. Explain how this inequality is related to your graph. 6. On your group graph, shade the region of the graph that represents Total scores that qualify for the team. Possible Solutions E X P L O R E E X P L O R E E X P L O R E Look for students who: clearly articulate the condition orally. (Total score > 60) can also mathematically represent this condition as an inequality. .4F + .6P > 60 are able to use the circled points on their graphs to help them graph the inequality. recognize that to graph an inequality in the coordinate plane requires the shading of a region. are wondering what to do when T=60; i.e., it is an important point; it is in the solution region. extend their shading to include the entire first quadrant or the entire coordinate plane, vs. those who limited their shading to the square bounded by the lines: F=0, F=100, P=0, P=100. LEARNING RESEARCH AND DEVELOPMENT CENTER Possible Questions You might ask: What does it mean to make the team? How could you write that using mathematics? What is the relationship between your circled points and the shaded region? What do the points with the stars indicate? What do they tell you? How did you decide how far to shade? Were there any parts of the graph for which you had a hard time deciding whether to shade them or not? © 2007 University of Pittsburgh Misconceptions/Errors Questions to Address Misconceptions/Errors Not considering points on the line T=60 as possible solutions. What is the lowest or minimum Total score that makes the team? Shading beyond the maximum and minimum “relevant” values. What is the maximum possible score on the x (F) and on the y (P) axis? What is the minimum possible score on the x (F) and y (P) axis? What would it mean if a point was out here (outside of the relevant domain and range of the context)? Funded by the James Irvine Foundation 10 Phase Task question: 7. Use the graph or equation to answer these questions: a. Suppose a skater scores 50 on the Short Program. What score does s/he need on the Prepared Dance to make the team? How did you find your answer? b. Pick a point in each of the regions and describe what that point represents. c. What are the x- and y-intercepts? What do they represent? 8. Describe what the shaded and non-shaded regions on your graph represent. 7c Possible Solutions Look for students who: Use the graph to answer the questions. Use the equation to answer the questions. Go back to their table to answer the questions. 7a. Minimum score L=66.7 gives T=60. 7b. Shaded region: Total score ≥ 60 – they made the team. Non-shaded region: Total score < 60 – they didn’t make the team. Possible Questions You might ask: (#7a) Which points on the graph represent scores of 50 on the Short Program? If a skater scores 50 on the 7c. x-intercept of the line 60=.4S+.6P is (150,0) which means a score of 150 on the Freestyle Dance and 0 on the Prepared Dance - which is impossible. y-intercept of the line 60=.4F +.6P is (0,100) which means a Freestyle Dance score of 0 and a Prepared Dance score of 100 to make the team. Freestyle Dance, how many scores can he or she obtain on the Prepared Dance to make the team? What is the minimum score? How do you know? (#7b) What do you know about the Total score for each point? What does it tell you about the dancer’s performance? (#7c) 8. See 7b above. Where are the x and y intercepts Misconceptions/ Errors Not having two clearly delineated regions on the graph. Students may not understand that a region with no shading is also a region. Questions to Address Misconceptions/ Errors Ask student (group) to graph the line .4F + .6P = 60 Ask students to show you on their graph where all the unacceptable Total scores lie – where the acceptable Total scores lie. Point to a point in the non-shaded region and ask students to explain why it is not circled. on the graph? What Freestyle and Prepared Dance scores would each of them represent? (#8) See questions for task question 6 and 7b. LEARNING RESEARCH AND DEVELOPMENT CENTER © 2007 University of Pittsburgh Funded by the James Irvine Foundation 11 Sharing, Discussing, and Analyzing Part 2 of the Task Orchestrating the mathematical discussion: a possible Sequence for sharing student work, Key Questions to achieve the goals of the lesson, and possible Student Responses that demonstrate understanding. Revisiting the Mathematical Goals of the Lesson: Begin to develop an understanding of inequalities in the coordinate plane and their use in representing mathematical situations and solving problems. Begin to develop an understanding of the relationship between inequalities and their graphs. Write inequalities to describe specific conditions in a situation. Evaluate algebraic expressions in two variables and interpret the results in terms of a mathematical situation. Begin to develop the ability to solve linear inequalities graphically. Interpret regions of the graph of linear inequalities in terms of the mathematical situation, and identify the solution region for a particular problem. Reason and solve problems using graphs and equations. Reason mathematically and use and make connections among a variety of mathematical representations. LEARNING RESEARCH AND DEVELOPMENT CENTER © 2007 University of Pittsburgh Funded by the James Irvine Foundation 12 Phase Sequencing of Student Work Rationale and Mathematical Ideas S H A R E This is a teacher-led discussion of the whole task. Students should be asked to reprise their work on the task and to summarize their thinking. Students should explain their thinking to each question using their graph, table or inequality to support their answers. D I S C U S S A N D A N A L Y Z E Graphs from various groups should be shown to the class for group discussion and critique of the qualities of the final graph. Important aspects of the graphs: boundary lines x-axis y-axis 60= .4F + .6P (starred) 2 regions non-shaded – .4F + .6P < 60 shaded – .4F + .6P 60 LEARNING RESEARCH AND DEVELOPMENT CENTER A discussion should follow about whether the graph, inequality or equation, or their table was most helpful in answering each of the questions. There should also be an encore of the discussion of the 2 regions of the graph in the context of the problem. This discussion is to ensure that all students understand the significance of the regions and where the solution region lies. A teacher-led discussion should address solid boundary lines, i.e., are the points on the line .4x + .6y = 60 included in the solution. The use of solid lines can then be introduced as a convention for representing points on the boundary that are part of the solution, if this has not been introduced previously. You can relate it to solid-circle (vs. open-circle) endpoints on graphs of inequalities on the number line © 2007 University of Pittsburgh Possible Questions and Student Responses This phase is the debriefing of the entire task. The “Key Questions” are the framing questions for the class discussion. Q1: What is the minimum Freestyle Dance score a dancer can receive and make the team? What score is required on the Prepared Dance to make the team with the minimum Freestyle Dance score? Explain how you know this. A skater can score a 0 on the Freestyle Dance but must receive a 100 on the Prepared Dance to make the team. I can see this on the graph – there’s a starred point at (0,100). I can see this in the equation since a Prepared Dance of 100 will give a total score of 60 even if someone gets 0 on the Freestyle Dance since 0 + .6(100) = 60. Ask students where to look on their graph to answer this question. Ask students to explain if a dancer can score a zero on the Prepared Dance and still make the team. Explain. No, a zero on the Prepared Dance will disqualify a skater. There are no starred points on the graph where L = 0. You can’t get 60 points if you get 0 on the Prepared Dance even if you score 100 on the Freestyle Dance since .4(100) = 40. Ask students where to look on their graph to answer this question. Is this question easier to answer using their graph or the equation? Relate this question to the student question, “Right now I have an average grade of 52 in your class. What do I have to make on my final in order to pass this course?” Funded by the James Irvine Foundation 13 Phase Sequencing of Student Work Rationale and Mathematical Ideas S H A R E Possible Questions and Student Responses Q2: A skater has a particular Freestyle Dance score. How can s/he figure out the minimum Prepared Dance score needed to make the team? The graph can give you an approximate answer, but solving the equation .4F +.6P = 60 will give an exact answer. D I S C U S S How can you graph the equation .4F + .6P = 60? I could find two points that work and connect them with a line. I could find the x and y intercepts by putting in zero for F and solving for P (giving the y-intercept), then a zero for P and solving for F (giving the x-intercept). A N D I could change this into the y = mx + b form and then I get P = 100 - A N A L Y Z E 2 F 3 How can you use the graph to answer the question? I find my Freestyle Dance score on the x-axis and then go straight up until I hit the line. I then go over to the y-axis to find the Prepared Dance score that goes with this passing point. How could you use the equation to answer the question? I substitute my Freestyle Dance score for S in the equation, then I solve the equation for L. This will give me the exact Prepared Dance score that will give me a Total score of 60. LEARNING RESEARCH AND DEVELOPMENT CENTER © 2007 University of Pittsburgh Funded by the James Irvine Foundation 14 CLOSURE Have students reflect on the mathematics of the lesson; find links to math that they have explored before; think of tasks that might be related to the big ideas of the lesson. It is important for students to step back and reflect on the ideas that surfaced and to situate their learning within past experiences and to think forward to ways that they might build on these ideas in future tasks. This helps them to focus on the interconnectedness of mathematical ideas. CLOSURE Pose the following question and allow time for students to discuss it in small groups: What would happen to the graph if you changed the Qualifying Total score to 70? HOMEWORK 1. What is the minimum Prepared Dance score a dancer can receive and still make the team? What score must they receive in the Freestyle Dance? Explain. 2. Are the minimum scores for making the team the same for both the Freestyle and Prepared Dances? Explain why or why not. LEARNING RESEARCH AND DEVELOPMENT CENTER © 2007 University of Pittsburgh Funded by the James Irvine Foundation 15 LEARNING RESEARCH AND DEVELOPMENT CENTER © 2007 University of Pittsburgh Funded by the James Irvine Foundation 16 “High School Dance Challenge” SCORES Freestyle Prepared LEARNING RESEARCH AND DEVELOPMENT CENTER © 2007 University of Pittsburgh “High School Dance Challenge” SCORES Freestyle Prepared Funded by the James Irvine Foundation 17