Chemistry help again?

Question

Nitric acid is an important acid used inmaking fertilizers, dyes, and explosives, among other things. The first step in the industrial production process is the oxidation of ammonia:
4NH3 (g) + 5O2 (g)------> 4NO (g) + 6H2O (g) Calculate the Heat of Reaction value, from Heat of Formation values:
NH3 (g)= -45.9 kJ: O2 (g)= 0 kJ; NO (g)= 90.3 kJ; H2O (g)= -241.8 kJ

Answer 1

(4 x 90.3) + (6 x -241.8) - (4 x -45.9)