12/21=4/7;
4/26=2/13;
10/90=1/9;
34/45=не делится,только если на 1.;
15/93=5/31;
15/95=3/19;
33/48=11/16;
62/108=31/54;
34/82=17/41;
105/200=5/8.
0.9*-8-0.9*3*4=-7.2-10.8=-18
1)
5 8/51 - 3 5/17 = 5 8/51 - 3 15/51 = 4 59/51 - 3 15/51 = 1 44/51,
2)
4 2/9 - 1 17/36 = 4 8/36 - 1 17/36 = 3 44/36 - 1 17/36 = 2 27/36 = 2 3/4,
3)
6 2/3 - 2 6/7 = 6 14/21 - 2 18/21 = 5 35/21 - 2 18/21 = 3 17/21,
4)
3 1/6 - 2 3/8 = 3 4/24 - 2 9/24 = 2 28/24 - 2 9/24 = 19/24,
5)
9 7/20 - 4 9/25 = 9 35/100 - 4 36/100 = 8 135/100 - 4 36/100 = 4 99/100