49+1/49-1+81+1/81-1+121+1/121-1+.9801+1/-9801-1
=1+2/6*8+1+2/8*10+1+2/10*12+……+1+1/98*100
=47+(1/6-1/8+1/8-1/10+1/10-1/12+……+1/98-1/100)
=47+(1/6-1/100)
=47又47/300
49+1/49-1+81+1/81-1+121+1/121-1+.9801+1/-9801-1
=1+2/6*8+1+2/8*10+1+2/10*12+……+1+1/98*100
=47+(1/6-1/8+1/8-1/10+1/10-1/12+……+1/98-1/100)
=47+(1/6-1/100)
=47又47/300