常用Excel运算符介绍_百度文库 http://wenku.baidu.com/link?url=oEANDo3h5gDqfdo-WHPPNfU51a5BBjUJVp9dCnYrE1MyPoyRiSMnyjH_PM-Vt5NHrLrlNufgyn38dCxXXPW9DjSEepeDndkex2PH8M2ih2C