①285-285÷19
②67.6÷13+0.8
③ × ÷ +
④( + )÷
⑤8.8×125
⑥ ×[ -( - )]
⑦4.5x-2.5=20
⑧x- x=
⑨x: =12:0.4
3x﹣1.5x=22.5
x:0.8=0.25:
1+x=
= 1.8:5.4=x:2.4 x:8=:
x﹣20%x=40 5x+18=48 :=15:x
7.2:x=
解:3.6x=57.6
3.6x÷3.6=57.6÷3.6
x=16