The number which best completes the sequence below is:
2 6 3 8 6 12 ?

I've seen a lot of IQ tests with patterns that seem to be similar to this one. If you look at the difference between consecutive numbers you may see it.

2 +4=
6 -3=
3 +5=
8 -2=
6 +6=
12

The differences alternate signs and the + value increases by 1 each time and the - value decreases by 1 each time. So the next number should be made with -1 so that's why I'm guessing that the next number is 11.