12÷1000= 2- = 0.7n+0.4n= 3+3×=
+= 8÷= 8÷0.8×= ×2+=
1.56-0.6= 42-32= 2.5×13×4= (968+632)×0=
①120+180÷5×6
②9.43﹣(0.39+2.43)
③
④
⑤()×14+
⑥