什么是四则混合运算是的哪四则

简介：At the gate of Qingyun Village, Jin Feng, Liu Qing, Qin Xiaotian and others were anxiously looking forward to their return. Finally, when the figures of the three people gradually appeared in front of everyone, everyone cheered and burst into laughter. They gathered around, and of course the most excited person was Liu Qing.