А) 7/16 -11/42 - 9/16 +17/42=7/16 - 9/16 +17/42-11/42=-2/16+6/42=-1/8+1/7=
1/7-1/8= 8/56 - 7/56=1/56
б) -1,23 + 2,14 + 7,38 - 5,77+1,62=-(1,23+5,77)+(7,38+1,62)+2,14=-7+9+2,14=2,14
в) -3и5/11 +1и3/8 +2и5/6 -4и6/11= -(3и5/11+4и6/11)+1и3/8+2и5/6 = -8+(1и6/24+4и20/24)=5и26/24-8=6и1/12-8=1и11/12
г) -9,39+0,74-10,61+3,26+6,25=-(9,39+10,61)+(0,74+3,26)+6,25=-20+4+6,25=-16+6,25=-9,75