Odd One Out — For the pairs 5–2, 19–16, 27–23, 31–28, three have difference 3. Identify the exception and explain.

Introduction / Context:
Checking constant differences is a fast way to classify number pairs. Here, three pairs share the same difference; one breaks it.

Given Data / Assumptions:

• Pairs: 5–2, 19–16, 27–23, 31–28.
• We compute difference as a − b or b − a consistently; since each pair shows a larger first number, we use a − b.

Concept / Approach:
Calculate the difference for each pair and compare.

Step-by-Step Solution:
5 − 2 = 3.19 − 16 = 3.31 − 28 = 3.27 − 23 = 4.Thus, three differences are 3; one is 4.

Verification / Alternative check:
Order does not matter for absolute difference: |5 − 2|, |19 − 16|, |31 − 28| are 3; |27 − 23| is 4. The outlier persists.

Why Other Options Are Wrong:

• 5–2: fits difference 3.
• 19–16: fits difference 3.
• 31–28: fits difference 3.

Common Pitfalls:
Switching to ratio checks complicates matters; the simplest invariant suffices here.

Final Answer:
27-23