Do Common Denominators Make Fraction Multiplication Easier?
Not really. You’ll recall from our basic overview of multiplying fractions that the denominator in the fraction is calculated by multiplying the two denominators from the numbers in the problem (the multiplicands). It doesn’t matter if these numbers are the same or different in the problem because the steps to find the denominator are the same.
But that doesn’t mean there aren’t a few tricks we can put to use when the denominators are the same here are a few to consider when you encounter a fraction multiplication problem, with or without common denominators.
Reduce Fractions Early If You Can
Just because the denominators are the same, you don’t need to leave them that way. If one of your fractions isn’t fully reduced, a good first step is to reduce that fraction so that multiplying the numerators and denominators is easier. If you’re facing a multiplicand that’s not already reduced, you’re know you’re going to have to reduce the product later. Go ahead and reduce that fraction now and save yourself from multiplying some needlessly large numbers!
Look for Opportunities to Cross Cancel
Like reducing, cross cancelling is another way to make numbers in your product smaller earlier in the steps of your calculation. If you can cross cancel before you multiply the numerator and the denominator, you’ll save yourself some extra work in the multiplication process because the numbers are smaller. And, you’re guaranteed to eliminate some reducing of the product to get your final answer. If you need some tips for cross cancelling, be sure to see my tips and tricks for cross cancelling.
