The difference between the greatest and smallest fraction amongst \(\frac {6}{7}, \frac {8}{9},\frac {9}{10},\frac {7}{8}\) is:
1
3 / 70
2
1 / 56
3
1 / 72
4
2 / 63
The difference between the greatest and smallest fraction amongst \(\frac {6}{7}, \frac {8}{9},\frac {9}{10},\frac {7}{8}\) is: