I'm assuming that the signs inside each circle is its sign. So, negative sign in the circle means it is a negative number and vice versa.
a.) Given:
7 circles w/ negative signs, 4 out of 7 circles are crossed out.
- 7 - 4 = -11
b) Given:
7 circles with positive sings and 5 circles with negative signs. The 5 negative circles are crossed out.
+ 7 - (-5) = 7 + 5 = 12
I'm not sure if I am correct but I answered based on what I understand from the given data.