Multiplying Fractions
Home > Lessons > Multiplying Fractions
Search | Updated December 26th, 2017
Introduction

    This lesson will inform you how to multiply fractions. Here are the sections within this lesson page:




    To multiply fractions it is important to know how to reduce fractions. It is strongly recommended that you review this lesson before progressing with the following sections.

    esson: Reducing Fractions


    There are many problems that require the multiplication of fractions. There are routine problems (determining how much paint to buy for a project) all the way up to applications problems (calculating how to mix chemicals to obtain a desired specific mixture). Here are two types of lessons in mathematics that require the multiplication of fractions.

    esson: Percent Word Problems
    esson: Work Word Problems

    The following section will help you understand how to multiply fractions.


    Like all skills within the realm of mathematics, there is a process to follow.

    For instance, determine what half of eight is. Intuitively, we know half of eight is four. This is what the mathematics looks like.

half of 8

    First, the word “of” refers to multiplication (most of the time).

half times 8

    Change the 8 to a fraction, 8 divided by 1.

half times 8

    Now, multiply straight across. Multiply numerator times numerator. Multiply denominator times denominator.

multiply 1/2 and 8

    We know that 8/2 means 8 divided by 2. So, we continue.

8 divided by 2

    Of course, this is a long way to go to take half of 8. However, it lets us know how to do more difficult problems.

    As an alternative method, we could have reduced fractions before we multiplied across the two fractions. Look at this point in the problem.

reducing multiplication problem

    We could have found a common factor between 8 and 2, which is 2. In other words, we can divide both the 8 and the 2 by 2, like so.

reducing multiplication problem

    Now we can multiply across.

multiplying fractions

    Reducing the problem makes it easier because the numbers are smaller, making the multiplication easier to perform.

    The following sections will reveal more difficult problems.


    Here is our first example.

multiplying fractions

    There are several ways to start reducing these fractions. Nevertheless, we can divide the 8 and the 4 by 4.

reducing multiplying fractions

    Now, we can divide the 6 and the 30 by 6, like so.

reducing multiplying fractions

    Since there is nothing left to reduce, we can multiply across.

multiplying two fractions

    ideo: Multiplying Fractions
    uiz: Multiplying Fractions


    Here is our second exmaple.

multiplying two fractions

    Before multiplying these fractions, first reduce a numerator with a denominator. We can divide the 15 and 25 by 5, like so.

reducing and multiplying two fractions

    Next, we can divide the 36 and the 20 by 4, like so.

reducing and multiplying two fractions

    Since there is nothing left to reduce with a numerator and a denominator, multiply across, as seen below.

multiplying two fractions

    ideo: Multiplying Fractions
    uiz: Multiplying Fractions


    Use this instructional video to learn how to multiply fractions.

    ideo: Multiplying Fractions


    Use this interactive quiz determine if you know how to multiply fractions.

    uiz: Multiplying Fractions


    Try these lessons, which are related to the sections above.

    esson: Divisibility Check
    esson: Fractions, Decimals, Percents
    esson: Reducing Fractions
    esson: Adding and Subtracting Fractions
    esson: Percent Word Problems
    esson: Multiplying Rational Expressions
    esson: Work Word Problems