35th ANNUAL CONFERENCE OF THE ATEE Budapest, august 26th – 31st, 2010. Development of concept of division – from intuitive models to division of fractions 0011 0010 1010 1101 0001 0100 1011 1 2 4 Maja Cindrić, Department for Teacher Education, University of Zadar, Zadar, Croatia mcindric@unizd.hr Irena Mišurac Zorica, Department for Teacher Education, University of Split, Croatia irenavz@ffst.hr What does we want for our children to acquire by learning mathematics ? 0011 0010 1010 1101 0001 0100 1011 • Kilpatrick and others (2001) : • conceptual understanding • procedural fluency • Strategic competence • Adaptive reasoning • Productive disposition 1 2 4 Figure1. : Interwined Strands of Proficiency, from Adding it up What does we want for our children to acquire by learning mathematics ? 0011 0010 1010 1101 0001 0100 1011 • Balance between conceptual understanding and procedural skills • ability to use a flexible application of knowledge learned in appropriate situations • combination of knowing the facts, knowledge of procedures and conceptual understanding • Students who memorized facts and procedures without conceptual understanding often are not sure when and how to use it so they know their knowledge is very fragile (Bransford and others 1998) 1 2 4 What does we want for our children to acquire by learning mathematics ? 0011 0010 1010 1101 0001 0100 1011 • Well connected and conceptually grounded ideas simply can be use in new situations (Skemp 1976) • practice algorithms in mathematics, without conceptual understanding are often quickly forgotten or remembered incorrectly • understanding of the concepts, without fluency in the performance of algorithms, may present an obstacle in solving problems 1 2 4 Contemporary mathematics curricula 0011 0010 1010 1101 0001 0100 1011 • emphasizes the optimal balance between the development of conceptual and procedural knowledge • many teachers are influenced by traditional teaching, which emphasizes practicing algorithms • teachers are aware of contemporary ideas, but do not feel confident to change the way teaching … • …or they don’t know how ? • to be sure we conducted research on understanding the concept of division 1 2 4 We asked ourselves : 0011 0010 1010 1101 0001 0100 1011 • what division means for children, students and mathematics teachers • What means to develop conceptual knowledge of division 1 2 4 Children's intuitive knowledge of division 0011 0010 1010 1101 0001 0100 1011 • even young children, can solve many different types of problem-solving tasks with direct modeling of problem situations in the task (Carpenter, Ansell, Franke, Fennema, Weisbeck, 1993) • Children are insistent in using intuitive knowledge despite the traditional methods explained by teacher 1 2 4 Children's intuitive knowledge of division 0011 0010 1010 1101 0001 0100 1011 • Mama sent Lucija to the store and gave her 100 kuna, to buy two cakes, and 3 packages of eggs. Each cake cost 15 kunas, a package of eggs, 11 kunas. Lucija wanted to buy a chocolate egg, which cost 3 kunas. Mom told her that with the rest money can buy what ever she want. How many chocolate eggs can Lucija buy? 1 2 4 Children's intuitive knowledge of division 0011 0010 1010 1101 0001 0100 1011 • all basic arithmetic operations are associated with the unconscious primitive intuitive model, which mediates in search of arithmetic operations needed to solve a mathematical problem (Fishbein 1985.) • two intuitive models that children use when the situation requires a division problem : • partitive model and measurement (quotative) model 1 2 4 Children's intuitive knowledge of division 0011 0010 1010 1101 0001 0100 1011 • On the table are 12 apples. I want to put apples into three baskets, so that contains the same amount of apple. How many apples are in each basket? "- Partitive division 1 2 4 • On the table are 12 apples. I want to put apples in the basket, so that in each basket contains three apples. How many baskets will be filled with apples? "- Measurment division Children's intuitive knowledge of division 0011 0010 1010 1101 0001 0100 1011 • Fishbein and others argue that intuitive models can impede, discourage or even prevent a child to solve mathematical problem • For 12 : 3 child is said : Grandfather has a 12 cookies and 3 grandchildren. How much cookies will each grandchild get? • For 3.21 : 0.75 child is said : Grandfather has a 3.21 cookies and 0.75 grandchildren. How much cookies will each grandchild get? 1 2 4 Definition of concept by Gerard Vergnaud 0011 0010 1010 1101 0001 0100 1011 • Concept is three-uple of three sets : C = (S,I,R) – S: the set of situations that make the concept useful and meaningful – I: the set of operational invariants that can be used by individuals to deal with these situations – R: the set of symbolic representations, linguistic, graphic or gestural that can be used to represent invariants, situations and procedures. 1 2 4 Class Multiplication problem Partitive division Measurment division Equal groups 3 children each have 4 oranges. How many oranges do they have altogether? 12 oranges are shared eqally among 3 children. How many does each get? If you have 12 oranges, how many children can you give 4 oranges to? Equals measures 3 children each have 4,2 liters of oranges juice. How much orange juice do they have altogether? 12,6 liters of orange juice is shared eqally among 3 children. How much does each get? If you have 12,6 liters of orange juice, to how many children can you give 4,2 liters? Rate A boat moves at a steady speed of 4,2 m/s. How does it move in 3,3 secondes? A boat moves 13,9 meters in 3,3 secondes. What is an average speed in meters per second? How long does it take a boat to move 13,9 meters at a speed of 4,2 m/s? Measure conversion An inch is about 2,54 cm. About how long is 3,1 inches in centimeters? 3,1 inches is about 7,84 cm. About how many centimeters are there in an inch? An inch is about 2,54 cm. About how long in inches is 7,84 cm? Multiplicative conversion Iron is 0,88 times as heavy as copper. If a pice of copper weights 4,2 kg, how much does a piece of iron of the same size weight? Iron is 0,88 times as heavy as copper. If a piece of iron weights 3,7 kg, how much does a piece of copper the same size weight? If equally sized piece of iron and copper weight 3,7 kg and 4,2 kg respectively, how heavy is iron relative to copper? Part/whole A colledge passed the top 3/5 of its students in an exam. If 80 students did the exam, how many passed ? A colledge passed the top 3/5 of its students in an exam. If 48 students passed, how many students sat the exam? A colledge passed the top 48 out of 80 students who sat an exam. What fraction of the students passed? Multiplicative change A piece of elastic can be streched to 3,3 times its original lenght. What is a lenght of a piece 4,2 meters long when is fully streched? A piece of elastic can be Stretched to 3.3 times its original length. When fully stretched it Is 13.9 metres long. What was its original length? A piece of elastic 4.2 meters long can be streched to 13.9 meters. By what factor is it lengthened? Cartesian product If there are 3 routes from A to B, and 4 routes from B to C how many different ways are there of going from A to C via B? If there are 12 different routes from A to C via B, and 3 routes from A to B, how many routes from B to C are there? Rectangular area What is a area of rectangle 3,3 m long by 4,2 m wide? If the area of rectangle is 13,9 m2 and the lenght is 3.3 m, what is the width? Product of measures If a A heather uses 3,3 kW per hour. For how long can it be used on 13,9 kWh of electricity? 0011 0010 1010 1101 0001 0100 1011 heather uses 3,3 kW of electricity for 4,2 hours, how many kWh is that? 1 2 4 Problems situations for division of whole numbers invented by elementary school children 0011 0010 1010 0100 1011 • for the1101 study0001 consisted of 135 • • • • elementary school children from 8 till 10 years old to write three problem tasks for which solutions will contain numerical expressions 12: 3, 45: 3 and 72: 12 How many children know to write a correct problematic situation? If the problem situation is the exact, a which classes of situation students choose and which division model If the child does not choose an adequate problematic situation, where he/she make mistakes 1 2 4 Problems situations for division of whole numbers invented by elementary school children 0011 0010 1010 1101 0001 0100 1011 True True Fals Fals Empty Partitive Measurment Partitive ∙ 0 12:3 65,9 28,9 5,2 96,6 3,4 41 59,3 33,3 7,4 86,5 1,1 46,6 50,4 34,1 15,5 95,6 1,5 39,1 45:3 72:12 + 1 5,1 2 - 41 4 4,4 2,2 2,2 2,2 31,1 43,3 Problems situations for division of fractions invented by elementary school children 0011 0010 1010 1101 0001 0100 1011 • subjects for the study consisted of 241 elementary school children in 6th grade • Students are asked to write one problem task for which solutions will contain numerical expressions 12: 1. 1 2 True True 5,8 Fals 42,3 Empty 51,9 2 4 Fals Partitive Measurment Partitive ∙ + 0 5,8 13,5 16,7 0 - 30,4 Problems situations for division of fractions invented by elementary school mathematics teachers 0011 0010 1010 1101 0001 0100 1011 • subjects for the study consisted of 122 elementary school mathematics teachers • Teachers from different schools in the southern Croatia (Split and Zadar County) • teacher was required to write three problem situations for three different division: 12: 3, 12: 12 , 12 : 34. 1 2 4 Problems situations for division of fractions invented by elementary school mathematics 0011 0010 1010 1101 0001 0100 1011 teachers True True 12:3 Fals Fals Empty Partitive Measurment Partitive ∙ 0 + 1 83,6 9 7,4 90,2 7,8 63,6 53,3 22,1 24,6 1,5 86,1 48,1 26 6,6 38,5 54,9 50 25 12,7 48,9 0 2 - 0 4 7,4 2,1 3,7 4,2 Problems situations for Division of Fractions invented by students from teacher studies 0011 0010 1010 1101 0001 0100 1011 • Subjects for this study consisted of 173 prospective teachers from University of Zadar and University of Split True True 12:3 Fals 1 Fals Empty Partitive Measurment Partitive 91,3 8,1 0 97,5 2,5 28,5 18,5 47,4 34,1 0 100 65,8 0,6 17,3 82 100 0 0 2 4 ∙ + - 7 0 21 3,7 2,4 3,7 43,3 3,3 10 Measurment model Equal gro up s Equal me as ure s Multipli Rate Partitive model Total c a t i v e c o n v e r s i o n Equal gro up s Equal m e a s u r e s Multiplicati ve co nv ers ion Rate Total Rectang ul ar ar ea 0011 0010 1010 1101 0001 0100 1011 2nd 4 t h g r a d e 1 0,7 1,5 0 0 2,2 45,9 5,9 11,1 2 0,7 0 0 0 0,7 40 4,4 12,6 3 0,7 0 0 0 0,7 28,1 3,7 16,3 g r a d e 1 2,9 2,9 0 0 5,8 0 0 students 1 1,2 0,6 0,6 0 2,4 86,1 2 17,9 0,6 0 0 18,5 3 0 0 0 0 1 0 6,6 0 2 32 13,9 3 0 0 6th teachers 0 62,9 1 0 57 0 48,1 0,7 2 4 1,5 1,5 0 0 0 0 2,3 0,6 0 89 0 0 0 0 0 0 0 0 0 0,6 0 0 0 6,6 67,2 5,7 2,5 0 75,4 1,6 0 0 45,9 0 0 0 0,8 0,8 6,6 0 1,6 1,6 0 0 2,5 0 2,5 1,6 0 0 Thank you ! 0011 0010 1010 1101 0001 0100 1011 1 2 4