2/1+6/5+12/11+20/19+30/29····9702/9701+9900/9899
=99-(2/1+6/1+12/1+20/1+30/1+……+9702/1+9900/1)
=99-(1-2/1+2/1-3/1+3/1-4/1+4/1-5/1+5/1-6/1+……+98/1-99/1+99/1-100/1)
=99-(1-100/1)
=98又100/1
=98.01
2/1+6/5+12/11+20/19+30/29····9702/9701+9900/9899
=99-(2/1+6/1+12/1+20/1+30/1+……+9702/1+9900/1)
=99-(1-2/1+2/1-3/1+3/1-4/1+4/1-5/1+5/1-6/1+……+98/1-99/1+99/1-100/1)
=99-(1-100/1)
=98又100/1
=98.01