Sapling- Chapter 1, #18

Formal Charge = Number of valence electrons - (lone pairs + 1/2 bonding)

Formal charge is the charge assigned to an atom in a molecule and it can be calculated by the formula up above. 

To find the formal charge in N:
5-(0 + 1/2 bonding)
5- (0+4)
+1

To find the formal charge in O:
6-(3 + 1/2 bonding)
6- (3+4)
-1

To find the formal charge on B:
3-(0 + 1/2 bonding)
3-(0+4)
-1

To find the formal charge on N:
5-(0 + 1/2 bonding)
5-(0+4)
+1

And you fill in your answers in accordingly!