Expert: Bobby Soltani - 8/16/2005

Question
Hello:

One method for simplifying a complex fraction is to multiply the terms by the least common denominator of the fractions.  In the example below all four simple fractions are multiplied by 36, the L.C.D.

(1/3 + 1/4)/(5/9 - 1/2) = (12 + 9)/(20 - 18) = 21/2 = 10 1/2

According to this method, there is no need to write this denominator, since in the division it cancels out.

Can you explain what this indicates? "There is no need to write this denominator, since in the division it cancels out."

I thank you for your reply.

Answer
Hi,

Not writing the denominator is essentially just skipping a step.  If you want to be complete, you should write the denominator, then perform the division.  So, the fraction would look like this:

((12 + 9)/36)/((20 - 18)/36) = (21/36)/(2/36) = 21/2 = 10 1/2

Let me know if you have any questions.

Bobby