Directions: Find the wrong number in the series. 196, 169, 144, 121, 100, 80, 64

### Concept & Logic Recognize familiar numerical sequences, such as perfect squares. ### Step-by-Step Solution 1. Observe the numbers: $196$, $169$, $144$, $121$, $100$, $80$, $64$. 2. Most of these are recognizable perfect squares. 3. $196 = 14^2$ 4. $169 = 13^2$ 5. $144 = 12^2$ 6. $121 = 11^2$ 7. $100 = 10^2$ 8. The next should be $9^2 = 81$. 9. The given number is $80$, which is not $81$. 10. The last number is $64 = 8^2$, confirming the pattern of descending squares. 11. Thus, $80$ is the wrong number in the series. ### Exam Strategy & Shortcut Memorizing perfect squares up to at least $30$ makes solving such series almost instantaneous. ### Common Pitfall Overcomplicating the pattern by looking at differences between terms when the numbers themselves are standard mathematical values (squares). ### Final Answer Therefore, the correct answer is **80**.