Multiple the fraction by 2,3,4,5
3/10 x 1 = 3/10 .... starting point
3/10 x 2 = 6/10 = 3/5 .... next multiple #1
3/10 x 3 = 9/10 .... next multiple #2
3/10 x 4 = 12/10 = 6/5 = 1 and 1/5 .... next multiple #3
3/10 x 5 = 15/10 = 3/2 = 1 and 1/2 .... next multiple #4
After multiplication, some of the results can be reduced (removal of common factors) or converted to proper fractions (i.e. by extracting whole numbers), e.g. http://statsfiddle.info/Primes/ReducedFractions/6?denominator=10