50米比40米多%;
的20%是250.
÷3= ×15= 2﹣ = 1+2%= ÷ =
5÷ = ×75%= ×4× = + × = ×99+99× =
① × - ÷
②1- ÷ -
③( + × )÷
④ ÷[( + )×2]
⑤ ×58+42÷8
⑥36×( + - )