Identify the odd term in the near-square sequence: 1, 4, 9, 16, 20, 36, 49.

Introduction / Context:
Most numbers listed are perfect squares. The task is to pick the single non-square. Knowledge of low squares (1^2 to 10^2) is sufficient to resolve such items quickly and reliably.

Given Data / Assumptions:

• 1 = 1^2
• 4 = 2^2
• 9 = 3^2
• 16 = 4^2
• 36 = 6^2
• 49 = 7^2
• 20 is not a perfect square

Concept / Approach:
Check each entry against the set of perfect squares. Since the surrounding values are exact squares, the non-square becomes evident.

Step-by-Step Solution:
Confirm squares: 1, 4, 9, 16, 36, 4920 lies between 16 (4^2) and 25 (5^2) and is not a squareTherefore, 20 is the odd term

Verification / Alternative check:
Square roots: √20 ≈ 4.472 (not integer), whereas √36 = 6 and √49 = 7.

Why Other Options Are Wrong:
1/9/49 are perfect squares and fit the pattern; removing them would break the natural square progression.

Common Pitfalls:
Misclassifying 49 (sometimes mistaken as non-square) or overlooking that 20 is not between any consecutive integer squares.

Final Answer:
20