几道令人抓狂的计算题、1.1× 2 × 3 + 2 × 4 × 6 +3 × 6 × 9…+200 × 400 × 60

1、1× 2 × 3 + 2 × 4 × 6 +3 × 6 × 9…+200 × 400 × 600
——————————————————————————————
1 × 3 × 5 + 2 × 6 × 10 + 3 × 9 × 15…+ 200 × 600 ×1000
=｛(1*2*3)*(1+2+…+200)｝/｛(1*3*5)*(1+2+…+200)｝
=(1*2*3)/(1*3*5)
=2/5
2、(1+1/51)*(1-1/51)*(1+1/52)*(1-1/52)*.*(1+1/152)*(1-1/152)
==(1-1/51)*(1+1/51)*(1-1/52)*(1+1/52)*.*(1-1/152)*(1+1/152)
=(50/51)*(52/51)*(51/52)*(53/52)*.*(151/152)*(153/152)
中间约分
=(50/51)*(153/152)
=75/76
3、题目确定吗?