1)2*1 5/12=2/1*17/12=17/6
2)4*1 1/8=4/1*9/8=9/2
3)1 1/9*1 1/4=10/9*5/4=25/18
4)17/6+9/2=17/6+27/6=44/6
5)44/6+25/18=132/18+25/18=157/18=8 13/18-это ответ
100•3=900:3
320:4=400:5
120+203>450-350
6/29 * (6 -24/11 * 14/9) = 6/29 * (6 - 112/33) = 6/29 * (198/33 - 112/33) = 6/29 * 86/33 = 172/319