72/4 + 3/4 = 75/4
_Ans._ 75/4.
In 18 are 72 fourths, plus the 3 fourths, equals 75 fourths.
To reduce two or more fractions to their least common denominator:
RULE.--Find the least common multiple of the given denominators for a
common denominator. Then for each new numerator take such a part of this
common denominator as the fraction is part of 1.
Reduce 1/2, 2/3 and 3/4 to their L. C. D.