①x﹣ =0.25
② x﹣ =120
③ =50%
①58+399=
②1122÷11=
③0.1÷=
④×54=
⑤0.24×5=
⑥1÷0.375=
⑦-=
⑧20÷10%=
⑨23+12=
⑩12×()=
⑪0.25×4÷0.25×4=
⑫+÷+=
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= .