什么是四则混合运算是的哪四则

简介：Meng Biao's humble expression and tone were very helpful to this servant who usually had a low status. He immediately smiled and replied, "Oh, it turns out that the messengers from the fifth master are here, hahaha, please come in quickly." Please come in, our Mr. Liu San has not seen the fifth master for a long time. Is he okay recently? Hahaha.