Question

1乘3乘5分之1+3乘5乘7分之1+5乘7乘9分之1.97乘99乘101分之1等于多少?

Answer 1

1乘3乘5分之1+3乘5乘7分之1+5乘7乘9分之1.97乘99乘101分之1

=1/4[1/1*3-1/3*5]+1/4[1/3*5-1/5*7]+...+1/4[1/97*99-1/99*101]

=1/4[1/1*3-1/3*5+1/3*5-1/5*7+...+1/97*99-1/99*101]

=1/4[1/1*3-1/99*101]

=833/9999