5乘8分之1+8乘11分之1+11乘14分之1+.+98乘101分之1
=（1/5-1/8+1/8-1/11+1/11-1/14+……+1/98-1/101）÷3
=（1/5-1/101）÷3
=96/505÷3
=32/505