20.5升=毫升=立方分米
+ 0.67 ×
÷ ÷5 × × ÷
÷ = ÷3= ×= × = 6× = 15÷ =
+ = - = 1- + = + - + =
① ÷7+ ×
②( + + )÷
③ + - +
④ + + +
⑤ ÷( - )
⑥ × ÷