0.75+0.25=
0.25×0.4=
0.32=
(3.6+5.4)-(3.6+5.4)=
0.87-0.8=
3.05÷100=
b+b=
0.8×2÷0.8×2=
①210÷35+12×109
②2.5×1.25×16
③()×12
④ [()]