Question

6分之1加12分之1加20分之1加30分之1加42分之1加56分之1等于多少

Answer 1

原式=1/2*3+1/3*4+1/4*5+1/5*6+1/6*7+1/7*8

=1/2-1/3+1/3-1/4+1/4-1/5+1/5-1/6+1/6-1/7+1/7-1/8

=1/2-1/8

=3/8