Question

Is 3/4 greater than 7/8?

Answer 1

$^{2/} \frac{3}{4} = \frac{6}{8} \\ \\ \frac{6}{8} < \frac{7}{8}$

Answer 2

3/4 = (2*3) / (2* 4) = 6/8

7/8.

Is 3/4 greater than 7/8? 
Is like asking is 6/8 greater than 7/8?  Because 3/4 is equivalent to 6/8.

The answer is No.