800-250+140:5•2

606

Reason:

• Interpret 140:5 as 140 ÷ 5, then × 2: (140 ÷ 5) × 2 = 28 × 2 = 56
• Then 800 − 250 + 56 = 550 + 56 = 606
• Follows order of operations (division and multiplication before additions/subtractions).