Chu Xinghe: There are 206 bones in the human body. My little friend is so romantic. Can I take out my spine and give it to him? Xie Chi: I can do 93 in Physics and 72 in Chemistry, but for you, I can only use the stupid student's method of substituting the data one by one. Can you tell me how to solve this difficult math problem of yours? The first time, spray lightly.