c) 2 1/2 = (2*2+1)/2 = 5/2
1 1/4 = (1*4+1)/4 = 5/4
5/2/5/4 = 5/2 * 4/5 = 2
d) 0,(2) = 2/9
0,(3) = 3/9
2/9/3/9 = 2/9 * 9/3 = 2/3
e) 2,1(3) = (213-21)/90 = 192/90
192/90/4/3 = 192/90 * 3/4 = 48/30 = 8/5
