1÷= = 1.1+0.11= 2.4×50%= 0.24÷0.8=
= 8×= 10﹣0.99= 0.22= 4×25%÷4×25%=
①2x+5.4=8.6
②4.5x+ x=70
③2.1:x=70%
④ :12= :x