We have to convert 10 mg to g first
10mg x (g / 10^3 mg) = 10 x 10^-3 g
Once we have the mass in grams, we can use the relationship of g/mol and use molar mass of NO2 to solve
10 x 10^-3 g x (mol NO2 / 46 g NO2) = 2.17 x 10^-4 mol NO2
Answer is 2.17 x 10^-4 mol NO2
