2) (6-2.43)/4.1/4
6-2.43=5(100/100)-2(43/100)=3(57/100)=3.57
3.57*4/17=357/100*4/17=(357*4)/(100*17)=1428/1700=21/25=0.84
3) 9.75/(4(1/2)-255)
4(1/2)-255=-250(1/2)
9.75/-250(1/2)=(39/4)/(-501/2)=(39/4)*(2/-501)=(39*2)/(-4*501)=78/-2004=13/-334=-13/334
4) 15.96/(9/25+2.04)
9/25+2.04=51/25+9/25=51+9/25=60/25=12/5=2.4
15.96/2.4=(399/25)/(12.5)=399/25*5/12=(399*5)/(25*12)=1995/300=133/20=6.65