Выполните действия
5/6*9/15-5/12*4/15
7/18*9/14+1/3*6/7
9/20*2/3+5/14*7/25
2,2/5*5/6-3/4*1,2/3
1,17/28*7/9+14/25*5/7
можно не кратко

1) 5/6 * 9/15 - 5/12 * 4/15 = 3/6 - 1/9 = 27/54 - 6/54 = 21/54 = 7/18;
2) 7/18 * 9/14 + 1/3 * 6/7 = 1/4 + 2/7 = 7/28 + 8/28 = 15/28;
3) 9/20 * 2/3 + 5/14 * 7/25 = 3/10 + 1/10 = 4/10 = 2/5;
4) 3 3/4 * 2/5 - 3 6/25 * 5/27 = 15/4 * 2/5 - 81/25 * 5/27 = 3/2 - 3/5 = 15/10 - 6/10 = 9/10;
5) 2 2/5 * 5/6 - 3/4 * 1 2/3 = 12/5 * 5/6 - 3/4 * 5/3 = 2 - 5/4 = 8/4 - 5/4 = 3/4;
6) 1 17/28 * 14/9 + 14/25 * 5/7 = 45/28 * 14/9 + 14/25 * 5/7 = 5/2 + 2/5 = 25/10 + 4/10 =
= 29/10 = 2 9/10