1) 7/2*30/38+87 = 7/2*30/125 =105/125 = 21/25
2) (5/6 +11/10)*24= (25+33/30)*24 =58*4/5=46,4
3) (19/8+11/12)*48/5= (57+22/24)*48/5=79*2/5 =31,6
4) 8*1/16 - 14/4= 1/2-14/4 =2/4-14/4 = -3
5) 6/9 -14/3=6/9-42/9 =-36/9=-4
6) 18,4/2,3=8
7) 0,6/-1,2=-0,5
8) 7/100 *(900^2)=7*8100=56700