Question

下图中第六小题怎么做?/\那个符号的意思的省略号.

Answer 1

原式= 1/2 + (1+2)/3 + (1+2+3)/4 + (1+2+3+4)/5 +……+(1+2+3+……+99)/100

= 1/2 + 1 + (1又1/2) + 2 + (2又1/2)+……+ (49又1/2)

= 1/2 * 50 + (1+2+3+……+49)*2

= 25 + (1+49)*49

= 2475