Question

1*2*3分之1+2*3*4分之1+3*4*5分之1————+48*49*50分之1=多少

Answer 1

/(1*2) + 1/(2*3) + 1/(3*4) + ... + 1/(49*50)

= 1/1 - 1/2 + 1/2 - 1/3 + 1/3 - 1/4 + ... + 1/49 - 1/50

= 1/1 - 1/50

ok!