MAKING PROBLEM SOLVING LESS PROBLEMATIC Prepared by SER Literacy & Numeracy Lead Coaches - 2013 What is problem solving? The term ‘problem’ and ‘problem solving’ occur in many subject areas, however, is most commonly associated with mathematics. ‘Solving a problem is finding the unknown means to a distinctly conceived end…to find a way where no way is known off-hand. For a question to be a problem, it must represent a challenge that cannot be resolved by some routine procedure. Problem solving is a process of accepting a challenge and striving to resolve it.’ (George Polya – ‘the father of problem solving’ 1945) Why teach problem solving? • An interesting and enjoyable way to learn mathematics. • An opportunity to learn mathematics with greater understanding. • Produces positive attitudes towards mathematics. • Teaches varied ways of thinking, flexibility and creativity. • Teaches general problem solving skills generally applicable in other KLAs and life. • Encourages cooperative skills. 3 The Importance of Problem Solving ‘With exposure, experience, and shared learning, children will develop a repertoire of problem-solving strategies that they can use flexibly when faced with new problemsolving situations.’ Burris, Anita (2005). Understanding the Math You Teach. Merrill Prentice Hall, ISBN 0-13110737-2 . 4 Australian Curriculum Why do children have difficulties with PROBLEM SOLVING? • When solving problems students will need to know general strategies and techniques that will guide the choice of which skills or knowledge to use at each stage in problem solving. • When a problem has ‘a new twist’ students cannot recall how to go about it – this is when general strategies are useful in providing possible approaches that may lead to a solution. • Some children find it difficult to think of ideas and strategies. A brain-storming session might help students reflect on problems they have previously solved. The misconceptions that students have, are a problem with the understanding proficiency strand rather than with fluency. When students don't understand something we can't fix it by just doing more of the same. Approaches to teaching problem solving … The approaches teachers use: Teaching for problem solving - knowledge, skills and understanding (the mathematics) Teaching about problem solving - experience-based techniques for problem solving, learning, and discovery that give a solution which is not guaranteed to be optimal and behaviours (the strategies and processes) Teaching through problem solving - posing questions and investigations as key to learning new mathematics (beginning a unit of work with a problem the students cannot do yet) Procedural ( Closed) and Open-ended Problems Procedural problems: One- or two-step simple word problems Open-ended problems: Problems that require mathematical analysis and reasoning; Open-ended problems can be solved in more than one way, and can have more than one solution. 8 Procedural or Open-ended? A typical conventional classroom task is: a Find the perimeter of this rectangle. 10 cm 4cm a A corresponding open-ended task is: a The perimeter of a rectangle is 28cm. What might be the length and width of the rectangle? Newman’s analysis of children’s problem solving errors 1. Reading Can students read the words of the problem? 2. Comprehension Can students understand the meaning? 3. Transformation Can students determine a way to solve the problem? 4. Process Skills Can students do the mathematics? 5. Encoding Can students record and interpret their answer? (cited in NAPLAN Numeracy 2009 by Bob Wellham K-12 Mathematics Consultant, Swansea) So what do we do? Help students to ……… - read the questions - comprehend what they read -provide strategies that aid understanding -teach students to check their answers are reasonable. In multiple choice questions – many students guess or are mislead. How can we do this? • Teach a problem solving model explicitly • Increase the mathematical metalanguage used • Train students to explain how they get their answers • Scaffold the teaching of the problem solving strategies • Assess for differentiation of learning • Explicit teaching of concepts Polya’s Model – Problem Sovling George Polya has had an important influence on problem solving in mathematics education. He stated that good problem solvers tend to forget the details and focus on the structure of the problem, while poor problem solvers do the opposite. Four-Step Process: 1. Understand the problem (See) 2. Devise a plan (Plan) 3. Carry out the plan (Do) 4. Look back (Check) Four Step Process Newman’s Analysis aligned with Polya’s model •See •Check •Plan 1.Reading the problem 2.Comprehending what is read 3. Carrying out a transformation from the words of the problem: the selection of an appropriate mathematical strategy 5. Encoding the answer in an acceptable written form 4. Applying the process skills demanded by the selected strategy •Do Step 1 – SEE: Understand the problem Students can be overwhelmed just by reading a problem. At this point group discussion is beneficial. Questions that may help you lead students to an understanding of the problem: •What are you asked to find or show? •What information is given? (valuable/useless?) •Has anyone seen a problem like this before? •Can you restate the problem in your own words? •What conditions/operations apply? •What type of answer do you expect/Can you give an estimate? •What units will be used in the answer? Visualisation Is an important way to read and understand the problem. Do I see pictures in my mind? How do they help me understand the situation? Imagine the situation What’s going on here? Drawing pictures/models: Using models to visualise/understand the problem Problem: Sally had some stickers. After she gave her best friend 280 stickers she had 754 stickers left. How many stickers did Sally have in the first place? Model drawing Sally had 1034 stickers in the first place. Step 2- PLAN: Devise a Plan 1. Is this problem similar to a problem you’ve done before? (Can you use the same method or part of the previous plan?) 2. What strategy would help you solve it? (Students can best learn skills at choosing an appropriate strategy by exposure to many different problems.) 3. Are the units consistent? Problem-solving strategies include: • Draw a picture or diagram • Act it out • Use concrete materials/make a model • Look for a pattern • Make an orderly list or table • Work backwards • Use direct/logical reasoning • Solve a simpler problem • Predict and test (guess & check) • Write an equation/use a formula • Eliminate possibilities Make a Drawing or Diagram • Stress that there is no need to draw detailed pictures. • Encourage children to draw only what is essential to tell about the problem. Act It Out • Stress that other objects may be used in the place of the real thing. • The value of acting it out becomes clearer when the problems are more challenging. Use concrete materials/ make a model • Students use materials to help them discover the relationship they need to see, to lead them to a solution. • Using concrete materials may make the problem easier to see. Look for a Pattern • This involves identifying a pattern and predicting what will come next. • Often students will construct a table, then use it to look for a pattern. • Explain to the students that: o They can look at a series of shapes, colours or numbers to see if you can find a pattern o The pattern should repeat o The pattern is not always obvious • Example: Look for a pattern using a table PROBLEM: Restaurants often use small square tables to seat customers. One chair is placed on each side of the table. Four chairs fit around one square table. Restaurants handle larger groups of customers by pushing together tables. Two tables pushed together will seat six customers. How many people will 4 tables pushed together seat? Number of tables Number of people 1 4 2 6 3 8 4 ? Construct a Table or Organised List • This is an efficient way to classify or order a large amount of data. • An organised list provides a systematic way to record computations. The letters ABCD, can be put into a different order: DCBA or BADC. How many different combinations of the letters ABCD can you make? To answer this question students may choose to make a list. By making a SYSTEMATIC list, students will be able to see every possible combination. Work Backwards • This strategy seems to have limited application opportunities, however, is a powerful tool when it can be used. • Some problems are posed in such a way that students are given the final conditions of an action and are asked about something that occurred earlier. Example of Working Backwards Direct /Logical Reasoning Explicitly teach students: •To tackle the problem step by step •That each piece of information is a piece of the puzzle, put all pieces together to find the solution •To read each clue thoroughly and work by a process of elimination •When the first plan (strategy) is unsuccessful, to try another one Solve a Simpler or Similar Problem • Some solutions are difficult because the problem contains large numbers or complicated patterns. • Sometimes a simpler representation will show a pattern which can help solve a problem. Teach the students to: · Set aside the original problem and work through a simpler related problem · Replace larger numbers with smaller numbers to make calculations easier, then apply same method of solving it to the original problem · Look for a pattern that may be emerging Predict & Test (Guess and Check) • This strategy does not include “wild” or “blind” guesses. • Students should be encouraged to incorporate what they know into their guesses - a logical guess. • The “Check” portion of this strategy must be stressed. • When repeated guesses are necessary, using what has been learned from earlier guesses should help make each subsequent guess better and better. Write an equation/ use a formula • Students can sometimes make sense of a problem by changing the written problem to a number sentence. Eliminate possibilities • Eliminating possibilities is a strategy where students use a process of elimination until they find the correct answer. • This is a problem-solving strategy that can be used in basic math problems or to help solve logic problems. Step 3 – DO: Carry out the plan • At this stage students need to follow the relevant steps to solve the problem. • They need to learn how to check each step of the solution and ensure the accuracy of the computation as they implement their chosen problem solving strategy. They need to be explicitly taught how to keep an accurate record of each step and how to avoid making careless mistakes and computational errors. Step 4 – CHECK: Look Back 1. Does my answer make sense? 2. Check the mathematics by working backwards, estimating, showing that the answer is reasonable, or doing the problem another way. 3. Have I answered the question? 4. Have I learned anything new from solving this problem? Polya’s Model in action Maddison, Bella, Tia and Talia all exchanged Valentine’s Day cards. How many Valentine’s Day cards were exchanged? See Understanding the Problem Do I understand all of the words? Exchange = swap Valentine = loved one Many = more than one What am I asked to do? I am asked to find out how many cards were exchanged between the 4 friends. Can I restate the problem in my own words? Four friends want to give each other a card. How many cards would be swapped if they were each to get a card from one another? Can I think of a picture or diagram that might help me understand the problem? Four Friends Is there enough information to enable me to solve the problem? Yes! Plan Devise a plan List Maddison Bella-Tia-Talia Bella Tia-Talia-Maddison Tia Talia-Maddison-Bella Talia Maddison-Bella-Tia Diagram Maddison Bella Tia Talia Act it out Three friends and I could stand in a circle. Each of us would hold enough pieces of paper to give one another one each. Then I could count how many pieces of paper we held altogether. Look for a Pattern Maddison would need *** Bella would need *** Tia would need *** Talia would need *** SO… ***+***+***+*** = 12 Solve a Simpler Problem If Maddison was to give a card to each of her three friends, She would need 3 cards. SO… There are four friends, each needing 4 cards. SO… 4 X 3 = 12 Write an Equation 4 friends each need to give out 3 cards. SO… 4 X 3 = 12 OR… 3 + 3 + 3 + 3 = 12 Problem Solving Think board What is the question asking? What information is important? Write your answer as a complete sentence. What strategy will you use to solve the problem? Attack the problem! Do the maths! DO