1.(1)0.2+0.2*3/7+4/7*0.2=0.2*(1+3/7+4/7)=0.2*2=0.4
(2)1-0.25+3/8÷1/3=1-0.25+3/8*3=0.75+1.125=1.875
(3)5/9*3/8+4/9*0.375=0.375*(5/9+4/9)=0.375
(4)1/50+1-2/5÷3/20=
2.x+130%x=460 60%x-43%x=34 x÷45%=2.4 16x-70=170
2.3x=460 0.17x=34 20/9x=12/5 16x=240
x=200 x=200 x=27/25 x=15