②x: =4: .
2.5+6=
0.12=
1-=
+=
1.5×20%=
24÷3%=
2400÷150÷2=
0.2×54=
0.052=
①1.5x-2.8=4.7
②
③12: =
x÷(1﹣ ﹣25%)=2 .
1 :4=x:2.5; 4.9+50%x=6.3; 6.9﹣ x= .