Which is greater? 6/7 or 98/100

First you need to get common dominators and then figure out from there

6/7 already reduced to the lowest terms;

the numerator and the denominator have no common prime factors:

6 = 2 * 3;

7 is a prime number;

98/100 = (2 * 72) / (22 * 52) = ((2 * 72) : 2) / ((22 * 52) : 2) = 49/50;