Răspuns:
Explicație pas cu pas:
a + b = 1/2 + 2/3 + 3/4 + 4/5 + 5/6 + 6/7 + 1/2 + 1/3 + 1/4 + 1/5 + 1/6 + 1/7 =
= (1/2 + 1/2) + (2/3 + 1/3) + (3/4 + 1/4) + (4/5 + 1/5) + (5/6 + 1/6) + (6/7 + 1/7) =
= 1 + 1 + 1 + 1 + 1 + 1 = 6
⇒ a + 2004 + b = a + b + 2004 = 6 + 2004 = 2010 ∈ N