Manuela Barden 1 Is Problem Solving the Trojan horse in your classroom? Manuela Barden “Oh!” exclaimed Chloe excitedly, “we can use that in our rule (when the sequence) doesn’t start with 1!” “Can we use variables?” Sally interjected looking at their writing on the board. Nodding Chloe continued: “…so the next step is to find half of whatever number is here (she points to the board)…so if that was 49 and that was 27 we would know that (the difference) is 22 and we need to find half of it. How do we show that? 1 Oh!” she exclaimed, and wrote ( y ! x ) on the board. 2 Conversation in a mathematics classroom, 2011 In this extract we are witness to the girls’ engagement with the problem in hand. It is not difficult to imagine these girls as successful problem solvers in a real life situation. Wiliam(2006) argues that effective participation in today’s society requires higher levels of critical thinking than 50 years ago. So what do students need to learn to become effective problem solvers? The research conducted by Project Zero, Harvard University graduate School of Education, identifies high level thinking as the precursor to problem solving. To facilitate thinking in the classroom, it must be made explicit and be the focus of learning. It becomes evident through observing students’ thinking whether they are simply following a procedure or actively engaging in problem solving. A 9 year siege, a Trojan horse and the city of Troy What does the story of the Trojan horse have to do with problem solving in the modern classroom? Traditionally I considered problem solving to be a topic in its own right and used strategies to teach it to my class. I usually presented 4 to 6 discrete approaches, from which students selected a method and used it to arrive at a solution. Although the expressions ‘guess and check’, ‘make a table’, ‘work backwards’, and ‘draw a diagram’ are often remembered long after the first encounter, this superficial understanding is not useful. Problem solving is about describing real life events in numbers so that connections can be made and patterns in the data found. Making a table is useful as it can illuminate these patterns, drawing a diagram and working backwards can identify relationships by looking at the information from different angles. Guess and check, a much abused strategy, is really the heuristic test and verify, and is a useful step to take when an intuitive sense of the answer is held, or all possible solutions have been reduced to a few. To approach a problem believing that the application of a strategy in its own right is the goal of problem solving kills off any opportunity for thinking. The students are separated from the very part of the activity that is engaging. “If you simply teach students how Manuela Barden 2 to solve problems they may learn very little other than the sequence of steps they need to follow in order to solve a particular type of problem” Killen (2006). When the presentation of strategies is followed by short oversimplified examples, Albert (2001) argues students are only involved in a brief recollection of facts and the application of formulae or rules. Using strategies to teach problem solving often eventuates in a classroom where very little thinking is happening. The Trojan horse left at the gates of Troy contained enemy soldiers. When the horse was taken inside the gates after the Greeks had appeared to flee, these soldiers stole out of hiding under the cover of dark and sacked the city. In the same way a dearth of thinking is encompassed in teaching strategies for problem solving. What kind of thinking supports problem solving? Much has been written about thinking in educational research and beyond. In their book Making Thinking Visible, Ritchhart, Church and Morrison develop the definition of thinking from a sequential activity, as described in Bloom’s taxonomy, to a more fluid exchange between high leverage mental moves. Tishman et al argues that thinking is something that needs to be developed and sustained in students: “…thinking and more specifically the disposition toward thinking…must be nurtured in students over time” (Tishman, Perkins, & Jay, 1993). Taken together with Wiliam’s belief that “Teachers do not create learning…teachers create the conditions in which students learn” (Wiliam, 2006), the paradigm shifts from teaching problem solving via strategies, to creating a thinking environment conducive to the solving of problems. Accepting this shift, the obvious next question is “do we all share the same understanding of what it means to think? Could we articulate what kinds of thinking we should support to assist problem solving in the classroom?” Ritchhart and his colleagues David Perkins, Shari Tishman and Patricia Palmer identify the following eight high leverage mental moves in response to these questions. • • • • • • • • Observing closely and describing what’s there Building explanations and interpretations Reasoning with evidence Making connections Considering different viewpoints and perspectives Capturing the heart and forming conclusions Wondering and asking questions Uncovering complexity and going below the surface Ritchhart, Church, Morrison (2011) Problem solving is a complex activity and requires a combination of the above mental moves. In Manuela Barden 3 my experience a lack of attention to detail and misinterpreting information are common stumbling blocks for students when problem solving. These issues directly connect to ‘Observing closely and describing what’s there’, the first thinking move in Ritchhart’s list. To examine this relationship more closely, I needed to be able to see what my students were thinking. In 2006 I was introduced to Thinking Routines through my involvement with The Ithaka Project, a network of teachers in Melbourne, Australia [http://ithakaprojecthistory.pbworks.com/w/page/34244604/The‐Ithaka‐Project]. Thinking routines require students to write down and/or discuss their thoughts, enabling teachers to “collect evidence about where the students are (so) as to make adjustments to our teaching to better meet our students learning needs” (Wiliam, 2006). Used within the International Baccalaureate Middle Years Programme (IB MYP), whose 4 program wide assessment criteria reflect the 8 high leverage thinking moves, thinking is placed at the center of student’s learning. Presented in this paper are my insights into how developing these eight thinking moves with a class of 25 Year 7 girls, improved their willingness to engage in problem solving, especially when the answer was no longer something that ‘the teacher knew and the student had to guess’. Students also became much more open to the idea that a solution could be reached by a variety of pathways, that ‘thinking’ involved effort, and there was useful thinking and not so useful thinking. Inside the walls of the classroom For the first session, my central aim was to build familiarity with the main routine I intended to use, See‐Think‐Wonder (STW) (Ritchhart, Church, Morrison, 2011). This routine addresses the first move in the list of ‘Observing closely and noticing what’s there’, and hence my concerns with students’ lack of attention to detail. The first step asks students to note what they see in the presented scenario (what details are you paying attention to?), then what they are thinking (what interpretations are you making based in these details?) and finally to record their wonders (what limitations are you considering?). Having worked with thinking routines in previous schools, I decided to use the approach of the Micro Lab protocol (Micro Lab) to structure the ensuing conversations. The first step is for the group of three or four students to spend two minutes silently reflecting on the STW that came up for them. Each student then has two minutes to present their thoughts to the group, who can make notes but not interrupt the speaker. Lastly the group has five minutes in which to collaboratively build a solution from the shared data and interpretations. As well as developing fluency with the routine, I was curious to see if any girls would invoke strategies learnt in previous years in the first few sessions. In response to the problem posed below, I was interested to see how the girls would deal with the specific terminology presented and whether they could express the concept of ‘consecutive’ algebraically. Manuela Barden 4 The sum of three consecutive numbers is 57 and their product is 6783, what are the numbers? DIAGRAM 1 • • • • • • • • • “How will I work this out?” “I wonder how to solve this problem” “I will need to multiply, I might need to add, I might use guess and check” “will I have trouble with this question” “I wonder if this is a trick question” “How will I know they are (the) right (numbers)?” “57 divided by 6783, long division” “nxaxb=6783, what is n, a, b? Do I divide or minus?” “Can they be the same number?” For many students in the first few sessions, their responses to the ‘think’ prompt were not interpretations of the facts but rather statements of what they were thinking at the time. Unconsciously my response to this was to repeat prompts that were interpretations to the class, and ignore those that weren’t. This implied qualification of what was a ‘strong think’ or a ‘poor think’ put the teacher back in the role of ‘she‐who‐knows‐everything’ a position that is not conducive to student thinking. At this point I was unsure of how to change this in the Manuela Barden 5 classroom. I was more content with the one‐to‐one conversations where I deliberately used the What‐Makes‐You‐Say‐That (WMYST) routine, eliciting justification with evidence. Some referred to the strategy guess and check, but it was interesting to note that in the five minutes for problem solving the students didn’t follow the strategy. One group did discuss the idea that they could try values less than 20 as 3x20=60. For those of us who understand what we are doing, this could be argued to be valid use of the strategy guess and check. However, for me this is the heuristic, test and verify. The students had to connect the problem to the expression 3x20 and then identify the set of values worth checking. Closing in on interpretations grounded in data I was pleased with the development of learning, but was keen to push thinking further. All students were able to identify the majority of key data, and even those with poor English skills completed this stage well. Students were invited to explain the meaning of difficult words prior to splitting into groups. However, I wanted more students to make useful interpretations of the data presented. The focus moved to the second high level thinking move in Ritchhart’s list “building explanations and interpretations”. In a discussion with colleagues, another routine called Zoom‐In was suggested. Like STW this routine asks students to notice the details and make interpretations, however, to further highlight how different pieces of information can affect a solution, the information is presented in layers. In this way students build several solutions to the problem, and witness how possible solutions vary as new data is taken into consideration. I continued to use the Micro Lab and the students, without direction, continued to use the language of STW. I purposely selected the following problem as it could be separated into layers that would direct students’ attention to key aspects of the question. At the same time this problem addressed the concept of shape and area the current topic of study. Christie made a cake in an 8in x 8in pan, which she wants to share with her 3 friends. She wants to divide the cake equally among all 4 people while giving each person a different shaped piece of cake. She wants one piece to be a triangle, one piece to be a quadrilateral, one piece to be a pentagon, and one piece to be a hexagon. Show how Christie can divide the cake. Explain how you know that each person received the same amount of cake? Mooney, March 2007 The first layer of the Zoom‐In routine is shown below with the subsequent layers, revealing the need for different shaped pieces, what the specific shapes should be, and finally the invitation to ‘show how’. Leaving this to the last reveal, I was interested in seeing which students would Manuela Barden 6 choose to use a diagram from the start. A diagram allows students to see the information from a different perspective often opening up their interpretation. Christie made a cake in an 8in x 8in pan, which she wants to share with her 3 friends. She wants to divide the cake equally amoung all 4 people. Explain how you know that each person received the same amount of cake. As expected, during the two minute round of individual thoughts, I heard a lot of girls say that the question was easy. I was intrigued to see that most students had represented a round cake before dividing it into quarters, despite the phrase “an 8inx8in pan”. The full question had been presented when the following responses to the ‘think’ prompt were recorded. DIAGRAM 2 • • • • “8in x 8in = 64 in pan” “Triangle – 3 sides, Quadrilateral – 4 sides” “Give each person 64/4= 16in then make a shape out of it” “What shape is the tin?” The two stumbling blocks were the shape of the pan and how to divide a shape into unequal parts. The first surprised me until I reflected that it is a common issue in the classroom where a teacher unwittingly only ever ‘uses’ round cakes. The second was another reason why I had selected this question. It nicely counterbalances the concept of fractions always having equal Manuela Barden 7 parts, which was reevaluated by students in a discussion on what to call the pieces. The evidence in this lesson suggested that the students’ thinking was becoming more ‘high level’. The students were embedded in building explanations. I was pleased to hear many of the conversations from the small groups carried on between lessons. Using problem solving to uncover misconceptions “Write down these decimals in order of size, from largest to smallest: 0.75 0.04 0.375 0.25 0.4 0.125 0.8. Underneath, describe and explain your method for doing this” Swan, 2006 I used Zoom‐In at the start of the next topic, fractions and decimals, instead of the more standard pre‐test. I was hoping the discussions would help students overcome their misconceptions, as opposed to just highlighting them to me. Equivalent area diagrams, line segments and percentage cards were used as the layers in the routine. Students could request the final layer of area diagrams and line segments divided into 100 equal parts if they felt they needed it. Manuela Barden 8 DIAGRAM 3 Sandra ordered her fractions as follows: “0.375, 0.125, 0.75, 0.25, 0.8, 0.4, 0.04”. In quite a fervent discussion with Wendy she said “0.375 is smaller than 0.250 because it was further away from 0”. Wendy found it difficult to explain why she disagreed with this, although she had placed 0.04 as the smallest fraction. After the first and second reveals of the area diagrams and percentages cards, both students were observed ordering the area diagrams correctly without referring to the ordered decimals. Asked to link the two together, Sandra saw that her decimal arrangement was incorrect but had difficulty accepting it. In their group Wendy alternated between calling the fraction 0.375, “zero point 3 hundred and 75 and zero point three, seven, five”. Discussion between the two and myself produced an ‘ah‐ha’ moment for Sandra, and a connection between the final layer area diagrams and decimals. At the end of the session the girls were asked to reflect on their learning. Sandra commented that it was easier to arrange the area diagrams as you could easily see which were smaller. Her final reflection captured this thinking. “When I started I didn’t understand decimals at all, I thought the decimals grew smaller and larger by the number of digits they had…the green (area) diagrams helped a lot because you could see how big they were”. Using problem solving to develop concepts As the sessions progressed, solving problems didn’t stay within the confines of one session every two weeks. The more I looked through resources for problems to use, the more I envisioned how particular problems could be used to answer questions arising from previous discussions. The next problem was chosen to further illustrate the necessity of defining the ‘whole’ that a fractional part is from, before being able to name it. At this point formal algorithms had not been discussed for adding fractions with different size denominators. However, some girls had experienced these at primary school. In addition to using the STW routine and Micro Lab, the girls recorded their STW on mini white boards. Some students found the semi permanence of the white boards more liberating when discussing tentative ideas. 1 of the pie and put 4 the rest back in the fridge. On Monday Jimmy took out the pie from the fridge and gave 1 to Kate. Who had the biggest slice of pie? 3 On Sunday Jimmy’s mother made a pie. Later that day Jimmy ate Manuela Barden 9 DIAGRAM 4 • • • • • Teacher: “Tell me about your board” Student: “Jimmy has ¼ of the cake and he gives Kate 1 third. So that’s sharing… dividing, so ¼ divided by 1 third…3 twelfths” Teacher: “WMYST” Student: (turning to her diagram by way of explanation) “The blue is the quarter of the cake Jimmy ate, leaving the white squares…which is the new amount to share into 3…so (Kate’s share) that’s the crosses…3 of the twelve squares” Student: (after further examination of her board) “ohh…the denominators…4 x 1 isn’t 12… that’s not right….maybe I shouldn’t be dividing?” This student was trying to make sense of the problem from two angles ‐ one by using a partially remembered algorithm, and one by the use of an area diagram. The temptation for the teacher is to tell students where they have misunderstood when looking at the diagram. The WMYST routine forces the student to articulate and hence follow their own reasoning steps. This aids them in uncovering any issues for themselves, and moves them into thinking more deeply about Manuela Barden 10 the question. Assessing students with regard to their thinking skills, supported by their solutions to problems, seemed to level the playing field. Neither end of the ability spectrum conformed to expectations. Those at the top were not guaranteed to be competent thinkers, and those at the bottom, when freed up to express themselves, proved to be more capable than expected. One student who seemed to be disconnected in class prior to this intervention couldn’t wait to share the following with me. She references a problem regarding the concept of proportion that the class tackled towards the end of the topic on fractions: “It was so funny yesterday miss. We were out to dinner, Niamh, Ciara and I and we were discussing the ‘Bear/Cookie’ problem and we realised the people at the table next to us were eavesdropping! It was so embarrassing! We’ve got a solution though, can we show you?” Conversation between student and teacher, 8:30am DIAGRAM 5 Recasting the role of the learner At the start of this process I was surprised how quickly the girls took to using the routines. As the sessions progressed and problem solving became more embedded, I noticed that some students continued to have difficulty building explanations. Use of Zoom‐In helped, but as is often the way with human beings, it didn’t work for everyone. I felt that some students in particular were jotting down everything that was on their mind in response to the think prompt, and allowing others to evaluate the relevance of their thoughts. I was reluctant to do this so as Manuela Barden 11 not to bring the ‘control of ideas’ back to myself, and yet I wanted these students to develop the ability to appraise their own ideas. I was worried that these students had fallen into a pattern of behavior that required little thinking. As Wiliam (2006) argues “Many students will resist (thinking) because thinking is hard. Henry Ford used to say that it’s extraordinary the lengths people will go to avoid doing it. Thinking is really hard and that’s the challenge: to create classrooms where it’s not optional”. Whilst attending a conference in Melbourne, I was inspired by Mark Church’s key note speech on ‘Instructional Core’. In this he argues how it is not enough to provide well‐chosen problems to solve but that the learner had to be empowered to reflect on their own thinking. In other words a key step in supporting thinking in the classroom was to have the students discuss which of the group’s ‘think’ statements had ‘legs’, what these statements had in common and build up a picture together of the qualities and features of ‘powerful thinks’ and ‘weak thinks’. The following problem was presented in the now fully accepted way using the Micro Lab and STW routine. The students engaged with the task straight away and clearly knew what was expected of them. They were keen to solve the problem themselves and used the teacher only as a facilitator. Routine use of the Micro Lab enabled each team member to contribute to the collaborative solution. Two communities in North Sydney, Caroll Gardens and Flatbush, each gather to make plans for an empty plot in their neighbourhood. The plots are identical in size, measuring 50m x 100m. In Caroll Gardens, the community group decides to allocate 3 quarters of the empty plot to playground and cover 2 fifths of this playground with asphalt. The Flatbush neighbourhood will devote 2 fifths of the plot to playground, and 3 quarters of the playground will be covered in asphalt. In which park is the asphalt greater? (Imm, Stylianou, & Chae, April 2008) Manuela Barden 12 DIAGRAM 6 The second of the two lessons on this problem starting with the class gathered around the solutions displayed at the back of the classroom. Having asked one student from each group to recap the interpretations they had made, the girls were invited to select ‘thinks’ that they saw as powerful. Some of their offerings are listed below. • • • • “linking ‘of’ to times” “drawing a digram with quarters horizontally and fifths vertically” “seeing the pattern in 3 quarters of 2 fifths and 2 fifths of 3 quarters” “making a diagram” In allowing students to evaluate their own thinking, I observed many ‘ah‐ha’ moments, especially regarding the drawing of diagrams. Having used diagrams in my explanations since the start of the year I had previously felt that students knew that was what I wanted of them, but didn’t value the reinterpretation of the information themselves, much like teaching strategies for problem solving. Summing up Over the past semester I have witnessed my students blossoming as thinkers and problem solvers. I have thought deeply about the type of thinking that is required to be a mathematician, how to construe questions in the classroom so as to invite thinking to take place and recasting the role of the learner in the classroom. Being part of a writing group provided a valuable opportunity for reflection and feedback. Inspired by the research of Harvard University School of education and the shift in paradigm to problem solving being the result of high level thinking moves, I was committed to bringing this into my classroom. At the start I wasn’t able to achieve the ideal of embedding problem solving, but made a start anyway. Manuela Barden 13 I was pleasantly surprised when the problem solving escaped from its imposed boundaries into almost every lesson. There was an abundance of resources both old and new in the staff room which reminded me that ‘problem solving’ is not a new approach in this subject. As well as the Mathematics Teaching in the Middle School (National Council of Teachers of Mathematics) journal I found the Questions and Prompts for mathematical thinking (Watson & Mason, 1998) to be very useful. This article describes a step in one teacher’s journey to deepen students’ understanding via problem solving in the classroom. As a result of the implementation of Thinking Routines, students have made their thinking visible to both teacher and themselves. Naming and noticing this thinking has empowered students to develop and improve their reasoning. The See‐Think‐ Wonder and Zoom‐In routines helped students connect to how a solution changes in response to each piece of data. The What‐Makes‐You‐Say‐That? routine prompted students to build explanations grounded in the data. I have approached the Trojan horse of ‘teaching strategies for problem solving’ by listening to Cassandra’s warning, that the Trojans foolishly ignored, that the wooden structure was not actually a gift, but a trap. References Devlin, K. J. (1998). The language of mathematics: making the invisible visible. New York: W.H. Freeman. Imm, K., Stylianou, D., & Chae, N. (april 2008). Student Representations at the Center: Promoting Classroom Equity. Mathematics Teaching in the Middle School, 13(8), 458463. Killen, R. (2003). Effective Teaching Strategies. Lessons from Research and Practice (3rd ed.). Tuggerah, NSW: Social Science Press. Mooney, E. (dec 2007). Solve It! The Three Bears Cookie Store. Mathematics Teaching in the Middle School, 13(5), 283. Mooney, E. (March 2007). Solve It!: Christie's Cake. Mathematics Teaching in the Middle School, 12(7), 379. Manuela Barden 14 Ritchhart, R., Church, M., & Morrison, K. (2011). Making Thinking Visible: How to Promote Engagement, Understanding, and Independence for All Learners. San Francisco, CA: Jossey-Bass. Space Shuttle. The Final Mission [Motion picture]. (2011). UK: BBC. Swan, M. (2006). Collaborative Learning in Mathematics [Scholarly project]. In The Standards Unit Materials. Retrieved August 29, 2011, from http://www.nanamic.org.uk/Conference%202006/Keynote%20address%202006.pdf Visible Thinking. (n.d.). Project Zero. Retrieved August 29, 2011, from http://www.pz.harvard.edu/vt/VisibleThinking_html_files/VisibleThinking1.html Watson, A., & Mason, J. (1998). Questions and prompts for mathematical thinking. Derby, [England: Association of Teachers of Mathematics.
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