a = 3×50 - 360 ÷ 9 + 2×45
a = 150 - 40 + 90
a = 200
b = 2×[320 ÷ 4 - (5 + 240 ÷ 8) ÷ 7]
b = 2×[80 - (5 + 30) ÷ 7]
b = 2×[80 - 35 ÷ 7]
b = 2×[80 - 5]
b = 2×75
b = 150
c = [(145 - 390 ÷ 3) + (230×2 - 150 ÷ 6)] ÷ 9
c = [(145 - 130) + (460 - 25)] ÷ 9
c = [15 + 435] ÷ 9
c = 450 ÷ 9
c = 50
a + b + c = 200 + 150 + 50 = 400 - Adevărat
a - b + c = 200 - 150 + 50 = 100 - Adevărat
a - b - c = 200 - 150 - 50 = 0 - Adevărat