Find the odd number out in the sequence: 10, 25, 45, 54, 60, 75, 80.

Problem restatementFrom 10, 25, 45, 54, 60, 75, 80, identify the single outlier.

Given data

• Sequence: 10, 25, 45, 54, 60, 75, 80

Concept / ApproachCheck divisibility patterns (by 2, 3, 5). The presence of many multiples of 5 suggests a quick screen.

Step-by-step validation 10 → divisible by 5 25 → divisible by 5 45 → divisible by 5 54 → not divisible by 5 60 → divisible by 5 75 → divisible by 5 80 → divisible by 5

All except 54 are multiples of 5; hence 54 is the outlier.

Verification / AlternativeDivisibility by 5 requires the last digit 0 or 5. Only 54 ends with neither.

Common pitfalls

• Checking only evenness—several terms are even, but that does not isolate a unique outlier.

Final Answer54