Question

简便计算求过程

1/1×2+1/2×3+1/3×4+1/4×5+1/5×6+1/6×7+1/7×8＋1/8×9+1/9×10
求过程，要简便计算

Answer 1

Answer 2

1/1×2+1/2×3+1/3×4+1/4×5+1/5×6+1/6×7+1/7×8＋1/8×9+1/9×10
=1/1-1/2+1/2-1/3+1/3-1/4+1/4-1/5+1/5-1/6+1/6-1/7+1/7-1/8＋1/8-1/9+1/9-1/10
=1-1/10
=9/10