+ + 2 = 4 1 = 5 2 = 4 2 3 2 = 4 − 5 = 5 − 2 = 4 − 5 = 5 − 4 2 = 4 − 10 + 4 = 0 2 = 2(2 − 5 + 2) = 0 (2 − 4) × (2 − 1) 2 − 2 = 0 2 − 1 = 0 1 = 2 = 2 = 2 + 2 + 4 = 70 = 7 = 70 = = 10