Multiple choice

Directions: In the following numbers, one number is incorrect. Find the odd number.

7, 11, 13, 17, 19, 21, 25, 29.

  1. 17

  2. 19

  3. 21

  4. 29
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

The series contains prime numbers (7, 11, 13, 17, 19, 25, 29), but 21 is not a prime number since 21 = 3 × 7. All other numbers are prime. So 21 is the odd one out.

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