a)17/8-2/5+0,2-0,1=17/8-2/5+2/10-1/10=10×17/10×8-16×2/16×5+8/8×10=
170-32+8 totul pe 80=73/40
b)-15/18-11/12+29/9-16/6=-60-66+232-192 totul pe 12×6=-86/72=-43/36
c)29/30-0,2(5)+27/5-0,3(1)=29/30-23/90+27/5-28/90=87-23+486-28 totul pe 90=64+458 totul pe 90=522/90=261/45
d)-18/36+1/9+0,1(5)-0,1(25)=-18/36+1/9+14/90-124/990=-12780/35640=-1278/3564=-639/1782= -213/ 594