18/85 : 27/68 * 45/28 : 12/77 =18/85 * 68/27 *45/28 *77/12=
=2/17 * 68/3 * 9/28 *77/12 = 2/1 * 4/3 * 3/28 *77/6 =2/1 * 4/3 * 3/4 * 11/6=
= 11/3 = 3 2/3
80/81 : 40/63 * 27/28 : 3/20 = 80/81 * 63/40 * 27/28 *20/3 =10
99/160 : 33/40 * 20/27 : 5/81 = 99/160 * 40/33 *20/27 * 81/5 =9
24/37 : 27/74 : 32/45 * 14/15 = 24/37 * 74/27 * 45/32 * 14/15=7/3=2 1/3