1/1*3+1/3*5+1/5*7+……+1/97*99+1/99*101
=(1/2)(2/1*3+2/3*5+2/5*7+……+2/97*99+2/99*101)
=(1/2)[(1/1-1/3)+(1/3-1/5)+……+(1/99-1/101)
=(1/2)(1/1-1/101)
=50/101
1/1*3+1/3*5+1/5*7+……+1/97*99+1/99*101
=(1/2)(2/1*3+2/3*5+2/5*7+……+2/97*99+2/99*101)
=(1/2)[(1/1-1/3)+(1/3-1/5)+……+(1/99-1/101)
=(1/2)(1/1-1/101)
=50/101