Odpowiedź:
a) 20 - (3 × 4 + 2 ) = 20 - (12 + 2) = 20 - 14 = 6
b) 20 - 3 × 4 + 2 = 20 - 12 + 2 = 8 + 2 = 10
c) 20 - 3 × (4 + 2) = 20 - 3 × 6 = 20 - 18 = 2