1.
1) 3/10 * 500 = 1500/10 = 150
2.
2/3 * х = 1,6
х = 1,6 : 2/3
х = 1 6/10 : 2/3
х = 1 3/5 : 2/3
х = 8/5 * 3/2
х = 24/10
х = 2 4/10
х = 2 2/5
3.
5:20 = 5/20 = 1/4
4.
4:х = 12:6
4:х = 2
х = 4 : 2
х = 2
5.
-12,4 + 3,2 = -9,2
6.
-45 - 12,7 = - 57,7
7.
-34 : 26 = - 34/26 = - 1 8/26 = -1 4/13
8.
3 * (-12,6) = - 37,8
9.
-2 1/3 : (-0,1) = - 7/3 : (-1/10) = -7/3 * (-10) = 70/3 = 23 1/3
10.
Не знаю (((((