Well, the best way to solve this is maybe just to find a pattern, so 2, 3, 1, -2, -3, -1, 2, 3, 1, -2, -3, -1, so we find out that it repeats and the sum is 0 every 6 terms! Now that we know this, We can just find out the last two digits, which are 2 and 3. So 5, which is our answer
