Question

What number should replace the question mark?

Answer 1

number should replace the question mark : 2

Comments

What is the logic?

Answer 2

ab
cd
a+c=b
a-c=d
1)8+1=9,8-1=7
2)3+2=5,3-2=1
3)5+2=7,5-2=3
4)4+2=6,4-2=2
so ans is 2