Решение дробей 2*5\3*6; 2*7\9*4; 3*5\20*2; 4*3\9*7; 10*3/23*10; 10*2\21*30; 4*5\15*16; 8*9\27*16:

 2 * 5/3 * 6 = (2 * 5)/3 * 6 = 10/3 * 6 = 60/3 = 20. 

2 * 7/9 * 4 = (2 * 7)/9 = 14/9 * 4 = 56/9 = 6 2/9. 

3 * 5/20 * 2 = (3 * 5)/20 = 15/20 * 2 = 30/20 = 3/2 = 1 1/2. 

4 * 3/9 * 7 = (4 * 3)/9 =  12/9 * 7 = 108/7 = 15 3/7. 

10 * 3/23 * 10 = (10 * 3)/23 = 30/23 * 10 = 300/23 = 13 1/23.

10 * 2/21 * 30 = (10 * 2)/21 = 20/21 * 30 = 600/21 = 28 12/21. 

4 * 5/15 * 16 = (4 * 5)/15 = 20/15 * 16 = 300/16 = 18 12/16 = 18 3/4. 

8 * 9/27 * 16 = (8 * 9)/27 = 72/26 * 16 = 1152/26 = 44 8/26 = 44 4/13.