5又1/3+3又1/15+5又1/35+7又1/63+9又1/99
=(5+3+5+7+9)+(1/3+1/15+1/35+1/63+1/99)
=29+1/2*(1-1/3)+1/2*(1/3-1/5)+1/2*(1/5-1/7)+1/2*(1/7-1/9)+1/2*(1/9-1/11)
=29+1/2*1-1/2*1/11
=29+1/2*10/11
=29又5/11
5又1/3+3又1/15+5又1/35+7又1/63+9又1/99
=(5+3+5+7+9)+(1/3+1/15+1/35+1/63+1/99)
=29+1/2*(1-1/3)+1/2*(1/3-1/5)+1/2*(1/5-1/7)+1/2*(1/7-1/9)+1/2*(1/9-1/11)
=29+1/2*1-1/2*1/11
=29+1/2*10/11
=29又5/11