6+7-3=10
14-8-5=11
11-3+6=2
12-4-7=1
8+7+1=16
6+9-5=10
X = 500+400
x = 900
................
44/45 * 3/5 = 132/225 132/225 * 10/11 = 1320/2475= 264/ 495
30/77 * 11/18 = 330/1386 = 55/231 55/231 * 3/25 = 165/5775= 33 / 1155= 3/105
20/13 * 39/100 = 780/ 1300 = 78 /130 78/ 130 *10/21 = 780 /2730=78/273 =26/ 91
X*6=(x+7)*2,5
6x=2,5x+17,5
3,5x=17,5
x=3
3/11<7/11
7/9>2/3(6/9)
7/18>7/24(28/72>21/72)
3/8<2/5(15/40<16/40)
2.2/5;3/4;4/3(24/60;45/60;80/60)
3.1;1/5;1/6;1/9(1;18/90;15/9010/90)
4.Например,6/41.