Question

计算这个有趣的算式1/1×2+1/2×3+1/3×4+````````+1/8×9+1/9×10（提示：1/1×2=1-

Answer 1

1/1×2+1/2×3+1/3×4+````````+1/8×9+1/9×10

=1-1/2+1/2-1/3+1/3-1/4+……+1/8-1/9+1/9-1/10

=1-1/10（因为中间两两消去了）

=9/10