Thanks for the query.

The numbers are continuing with + 1, - 2. Like 1 + 1 = 2 and 2 - 2 = 0 and again 0 + 1 = 1.

So, the answer should be 1 - 2 = -1 and -1 + 1 = 0.

If abcde=1 (where a,b,c,d and e are all positive real numbers) then what is the minimum value of a+b+c+d+e?

If a/b = 21/34; b/c = 121/120; c/d = 17/77; e/f = 11/15 and d/e = 14/17 then what is the value of (abc/def)*2?