× = ×2= - = + = ÷3=
20× = 2.5×0.1= 7.5÷0.5= 15÷ = ÷ =
①3.7× +6.3÷
②( - )×( + )
③101×
④ ÷[ ×(-)]
⑤7÷ - ÷7
⑥ ÷[( + )÷ ]