1) 1/2 + 5/6 =3/6+5/6=8/6=4/3
2)4/3-7/9 = 12/9 -7/9 =5/9
3) 5/9 :1 2/3 = 5/9 * 3/5 = 1/3
4) 15 : 2,4=6,25=6 1/4
5) 6 1/4 - 6 1/36 = 6 9/36 - 6 1/36 = 8/36 = 2/9
6) 1/3 :2/9 = 1/3 * 9/2 = 3/2
7) 2,75 - 2/3 = 2 3/4 - 2/3 = 2 9/12 - 8/12 = 2 1/12 = 25/12
8) 25/12 *1.2 = 25/12 * 12/10 = 5/2
9)7/30 + 5/12 = 14/60 + 25/60 = 39/60 = 13/20
10) 13/20 : 0,13 = 13/20 * 100/13 = 5
11) 5/2 : 5 = 5/2 * 1/5 = 1/2
12) 3/2 + 1/2 = 1,5+0,5=2
13) 2 : 0,125 = 16
ответ: 16