2)1:8/13=3)9/16:36=4)2 13/16:4 3/8=​

2)1:8/13=  1 * 13/8 = 13/8 = 1  5/8

3)9/16:36=  9/16 * 1/36 = 9/576 = 1/64

4)2 13/16:4 3/8=​ 45/16 : 35/8 = 45/16 * 8/35 = 360/560 = 8/13