( 1- 2/2) X ( 1-3) X ( 1- ¼) X ( 1 – 5) X ( 1- 6) X ( 1 – 7...

1/2 x 2/3 x 3/4 x 4/5 x 5/6 x 6/7

= 1 x 2 x 3 x 4 x 5 x 6 / 2 x 3 x 4 x 5 x 6 x 7

= 1/7

Đáp số: = 1/7