四则混合运算是哪四则

简介：An Ruyi had nothing to do while playing Tai Chi with Su Can, chatting about everything from the southeast to the northwest, from national affairs to trivial matters, to astronomy, geography and human geography. Su Can actually knew a little about everything, and kept talking, which made An Ruyi understand everything. Ruyi almost couldn't resist, there was a faint stream of sweat on her forehead, making the strange red lotus look even weirder.