Fractions 101 for Parents

The important topic of Fractions is usually introduced in upper elementary levels. Here we highlight some changes in the way we teach fractions in recent years.

Procedural vs Conceptual Understanding

Traditionally, fraction operations were taught using procedures. Conceptual understanding comes after students use the tools they learn to solve problems. For example, ¾ x 12, students were taught to look for the greatest common factor (GCF) between the numerator (12) and denominator (4) and simplify, i.e.

fraction_of_a_set_simplification

This leads to common mistakes like these

mistake_fraction_1

mistake_fraction_2

Without conceptual understanding, the student who made these errors do not have the intuition to realize that something is not right.

Fraction of a Set

Today, for elementary operations in Fractions, we start with conceptual understanding (with the aid of pictures), before introducing procedures. For example, a typical Fraction of a Set problem such as 1/3 of 24 can be visualized as

two-thrids-of-24

Students are invited to explore the reasoning behind the procedure of “canceling” numerator and denominator, by showing 2/3 x 24 = 2 x 24/3 = 2 x 8, hence two-thirds of 24 is the same as two groups of 8.

Fraction Addition

Fraction addition (and subtraction) is another topic in Fractions where traditional procedural-focused approach is being replaced by more conceptual understanding in recent years. In particular, the “butterfly” method is a common trick taught to students in elementary schools. Here, a common multiple in the denominators is found by multiplication and the numerators are converted by cross multiplication.

butterfly_method

This does not help in understanding fraction addition at all! Moreover, such tricks are often not easy to extend, e.g.

butterfly_method_extension

Today, we teach fraction addition using a Concrete-Pictorial-Abstract progression.

Concrete: Start with the fraction wheel as a concrete manipulative, let the students work with simple examples such as 1/2 + 1/4, 3/4 + 1/8 etc.

fraction-wheel

Pictorial: Transfer the problem to pictorial form. Start with the circle as it is most similar to the fraction wheel,

cpa-pictorial

then translate the problem to the bar model,

cpa-pictorial-bar-model

Abstract: Finally, present the problems in their abstract form,

cpa-abstract

With a more solid grounding in conceptual understanding, students are able to understand how the procedures work later on, and more important, are more able to translate fraction word problems into the necessary equations.

Concept of the same whole

In drawing pictures for fractions, we always draw the fractions as part of the same object or the “same whole“. This is a very important concept that students need to understand. If fractions are presented pictorially as referring to different wholes, it is easy for the students to get confused. For example,

For example, the following is a very common mistake where students see 8 equal parts, and therefore, use 8 as the denominator!

same-whole


More Fraction Resources

For more fraction resources, refer to our main fractions page.

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