6/11*4/7=7/20*10/21=8/9*27/32=23/28*49/46=34/86*43/51=7/18*90/77=63/64*48/91=19/100*5/38=

6/11 * 4/7 = (6*4)/(11*7) = 24/77
7/20 * 10/21 = (1*1)/(2*3) = 1/6
8/9 * 27/32 = (1*3)/(1*4) = 3/4
23/28 * 49/46 = (1*7)/(4*2) = 7/8
34/86 * 43/51 = (2*1)/(2*3) = 2/6 = 1/3
7/18 * 90/77 = (1*5)/(1*11) = 5/11
63/64 * 48/91 = (9*3)/(4*13) = 27/52
19/100 * 5/38 = (1*1)/(20*2) = 1/40