Lowest common denominator for 13 and 20?

Answer 1

http://www.helpwithfractions.com/least-common-denominator.html

The least common denominator is the bottom number of a fraction you have the

Numerator

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Denominator

If you are looking for the least common denominator you would simply find the least common multiple. This is made easy by http://www.analyzemath.com/Calculators_3/lowest_common_multiple.html

Once you have found that you have the number that should be on the bottom then to make the fraction correct you would simply multiply the Numerator by the same amount you had to multiply the denominator to get that number.

In the example of 2/4 and 5/8 the LCD and LCM is 8 so you would multiply 4 by 2 to get 8 then you would also multiply 2 by 2 to get 4 making the fractions now 4/8 and 5/8.