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How to Multiply Fractions Using the Cancellation Technique

You can cancel fractions before multiplying them to make the calculation less complicated. It is usually required that after working with fractions you present your answer in its simplest terms. The advantage of using cancellation before multiplication of fractions is that your answer will most likely already be in its simplest terms without any further cancellation after you perform the multiplication.

Instructions

- 1
  Check to see if cancellation is possible. The numerator of one of the fractions must be a factor of the denominator of the other fraction and/or the denominator of one of the fractions must also be a factor of the numerator of the other fraction.
- 2
  Perform the cancellation. For example, if you were performing the calculation [3/6 * 12/16] you would be able to divide the numerator of the second fraction [12] by the denominator of the first fraction [6]. This cancels the denominator of the first fraction from [6] to [1] and the numerator of the second fraction from [12] to [2]. The resulting calculation is [3/1 * 2/16].
- 3
  Perform the multiplication. If you were to perform the multiplication before the cancellation above your result would be [36/96], which cancels to [3/8]. However, your result after the cancellation would be [6/16] which is much simpler to divide by two and achieve the same result, [3/8].

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