Сократите: 1)9*16/8*27; 2)8*28/35*12; 3)2*3*5/4*9*25; 4)7*13-7*2/35*9+35*2. / - это

1)
9*16/8*27 = 2/3;
2)
8*28/35*12 = 4*2/5*3 = 8/15;
3)
2*3*5/4*9*25 = 1/5*2*3 = 1/30;
4)
7*13-7*2/35*9+35*2 = 7*(13-2)/35*(9+2) = 7*11/35*11 = 7/35 = 1/5