1 + 2 = 3

Are you good in first-class mathematics with addition and subtraction of 3 digits 1, 2 and 3? Do you think that this is elementary for you? Let's check on what you're capable of? Solve simple mathematical examples, consisting only of additions and subtractions of numbers 1, 2 and 3, choose the correct answer before the expiration of the term and train the brains.