Question

1 1 1 ____ +____ +...+_______ 1*2 2*3 199*200 =(?) =(?) =(?)

Answer 1

1/1*2+1/2*3+1/3*4+1/4*5+...1/198*199+1/199*200

=(1-1/2)+(1/2-1/3)+...+(1/199-1/200)

=1-1/2+1/2-1/3+...+1/199-1/200

=1-1/200

=199/200