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By Adam Williams. Ambivalent Equivalence. Equiva what? . The concept of equivalent fractions is difficult for many students to ascertain and fully understand.
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By Adam Williams Ambivalent Equivalence
Equiva what? • The concept of equivalent fractions is difficult for many students to ascertain and fully understand. • Many of these difficulties can be attributed to a heavy emphasis on procedural knowledge and symbolic rules in early grades. (Tanner, 2008)
Standards • Understand representations of simple equivalent fractions. (3rd Grade, 4th Grade) • Add and subtract fractions and mixed numbers with common denominators. (4th Grade) • Find equivalent fractions and simplify fractions. (5th Grade) • Explore finding common denominators using concrete, pictorial, and computational models. (5th Grade) • Add and subtract common fractions and mixed numbers with unlike denominators. (5th Grade)
3rd Grade • Fraction Kit (Burns, 2009) • The teacher gives the students five strips of construction paper. The students cut and label the strips into different sized fractions.
Uncover • Students play in pairs, each starting with their whole strip covered by two halves. • They take turns rolling a six sided cube with the faces numbered one-half, one-fourth, one-eighth, one-eighth, one-sixteenth, and one-sixteenth. • The fraction that comes up tells the students what size fraction to remove to uncover the whole. • If they can’t remove a piece, they wait until their next turn or take the option of exchanging any of their strips for others in their kit, so long as it is an equivalent exchange. • The goal is to be the first person to completely uncover their strip. Playing the Game
4th Grade • Word problems such as these reinforce what the students have learned in previous grades. • They could easily use manipulatives to solve these problems, without forcing new material upon the students that may be frustrating to fourth graders. • Pattern blocks are a great way for students to visualize fractions and create better connections between addition and equivalency. I ate half a pizza and you ate one-eighth of the pizza. How much is left? My dog ate one-third of my sandwich, and my sister ate one-sixth. How much is left for me? A caterpillar ate three-fourths of an apple and a ladybug ate one-tenth more. How much is remaining? (Naylor, 2003)
Fraction Clothesline • A task that evokes this higher level thinking must be extremely interactive and promote group speak. • To accommodate this type of learning, Tanner (2008) recommends setting up a few clotheslines throughout the classroom.
Fraction Clothesline (cont.) • Each group should be given a set of cards that include several fractions (mixed and regular). In small groups, the students should take clothespins and put their fractions in order from least to greatest. • To incorporate equivalency, teachers can put equivalent fractions in with the others and observe how the students respond.
5th Grade • In the fifth grade, students move into the world of unlike denominators. • To help ease students into this process, manipulatives and visualization should be the first method of representing this operation.
Unlike Denominators • Let’s say the problem provided is 1/3 + 1/2 = X. • First, the students would use a hexagonal block to represent a whole. • They would divide it into thirds by finding the correct shapes (the blue rhombi) and placing them on top of the whole. • To represent one third, they take away two of the pieces and have the first fraction of the problem. • The students repeat the process with one-half, using a hexagonal piece as the whole and a red trapezoid to close in the half. • In order to add, the students must combine the fraction blocks together.
Unlike Denominators (cont.) • When the problem involves finding a solution greater than a whole, the students must take things a step further. • If the problem provided is 5/6 + 2/3 = X, the students will build their fractions much like in the previous problem. • When the students attempt to combine the pieces, they will notice that it is impossible to fit them all together. • The teacher should then guide the students into trying to create a whole using the provided pieces, and then use the remaining pieces to create the numerator and denominator of the mixed fraction. • Once they create a whole, they will use the excess parts to build a fraction to go along with it. In the case of this problem, it would be 1/2. This leads to the final solution of 1 1/2.
Conclusion • In order to be comfortable with fractions in the later grades, students must build a firm foundation early on. • It is important for students to experience a differentiation of methods when learning about fractions, because there are multiple types of learners and many different levels of understanding.
References Burns, M. (1999). Equivalent fractions and subtraction strategies. Instructor , 113 (5), 17. Duke, R., Graham, A., & Jonston-Wilder, S. (2008). The fractionkit applet. Mathematics Teaching Incorporating Micromath(208), 28-31. Naylor, M. (2003). Fill in the fractions. Teaching Pre K-8 , 33 (8), 28-29. Naylor, M. (2003). Putting the pieces together. Teaching Pre K-8 , 33 (5), 28-29. Rickard, C. (2007). Misunderstanding of fractions. Mathematics Teaching , 205, 32. Tanner, K. (2008). Working with students to help them understand fractions. APMC , 13 (3), 28-31.