To solve this problem, we need to simplify each of the fractions first.

1; 1/2 = 1 + 1/2 = 2/2 + 1/2 = 3/2
1; 1/3 = 1 + 1/3 = 3/3 + 1/3 = 4/3
1; 1/4 = 1 + 1/4 = 4/4 + 1/4 = 5/4
1; 1/5 = 1 + 1/5 = 5/5 + 1/5 = 6/5
1; 1/6 = 1 + 1/6 = 6/6 + 1/6 = 7/6

Now, we can rewrite the expression using the simplified fractions:

3/2 • 4/3 • 5/4 • 6/5 • 7/6 - 1/2

Next, we can multiply the fractions together:

(3 4 5 6 7) / (2 3 4 5 6) - 1/2
= (2520) / (720) - 1/2
= 1260/720 - 1/2
= 63/36 - 1/2
= 21/12 - 1/2
= 21/12 - 6/12
= 15/12
= 5/4

Therefore, the final answer is 5/4.