1%+2%+3%+4%+•••+98%+99%+100%=（1+2+3+4+•••+98+99+100）%=[（1+100）*100/2]%=5050%=50.5
1%+2%+3%+4%++98%+99%+100%=1/100×(1+2+3+......+100)=1/100×100/2×(1+100)=50.5
