Question

Which number will come in place of the question mark in the following series: 3, 4, 3, 0, -5, -12, ?

Answer 1

The answer is -21.
3
3+1= 4
4+1-2= 3
3+1-4= 0
0+1-6= -5
-5+1-8= -12
-12+1-10= -21

Answer 2

-21
Pattern: +1, -1, -3, -5, -7, -9...

Comments

your answer looks more rational and easy to understand