Any two fractions will do if the denominator equals the sum of the two numerators.
The numerators worked excellently, with a pedantic exactitude almost absurd.
Reduce the fractions to like denominators, add their numerators and write the denominator under the result.
Reduce the fractions to like denominators, subtract the numerators and write the denominators under the result.
Multiply the numerators together for a new numerator and the denominators together for a new denominator.
The numerator of the third is the sum of the numerators of the first and second, its denominator, the sum of the two denominators.
Simple division equations with numerators over denominators were reformatted as numerators/denominators.