Mensa IQ Test Mensa IQ Odd One Out Puzzles 1 — Questions and Answers
Question 1: Which number does NOT belong in this group: 2, 3, 5, 7, 9, 11, 13?
- 9 (Correct answer)
- 2
- 11
- 7
Correct answer: 9
All other numbers are prime (divisible only by 1 and themselves), but 9 = 3 × 3 is composite. It is the only number in the set that has factors other than 1 and itself.
Question 2: Which shape does NOT belong: circle, oval, sphere, square?
- Square (Correct answer)
- Circle
- Oval
- Sphere
Correct answer: Square
Circle, oval, and sphere are all based on curves with no straight edges or angles. A square has straight sides and right angles, making it fundamentally different from the curved shapes.
Question 3: Which number is the odd one out: 1, 4, 9, 15, 25, 36?
- 15 (Correct answer)
- 1
- 25
- 36
Correct answer: 15
1, 4, 9, 25, and 36 are all perfect squares (1², 2², 3², 5², 6²). 15 is not a perfect square — it cannot be expressed as any integer multiplied by itself.
Question 4: Which word does NOT belong: Dog, Cat, Fish, Chair, Bird?
- Chair (Correct answer)
- Fish
- Dog
- Bird
Correct answer: Chair
Dog, cat, fish, and bird are all living creatures (animals). Chair is an inanimate piece of furniture, making it categorically different from the rest.
Question 5: Which number does NOT fit the pattern: 8, 27, 64, 100, 125?
- 100 (Correct answer)
- 8
- 27
- 125
Correct answer: 100
8=2³, 27=3³, 64=4³, 125=5³ are all perfect cubes. 100 is not a perfect cube (4.64³ ≈ 100), making it the odd one out. 100 is actually 10², a perfect square.
Question 6: Which figure does NOT belong: triangle, square, pentagon, circle, hexagon?
- Circle (Correct answer)
- Triangle
- Pentagon
- Hexagon
Correct answer: Circle
Triangle, square, pentagon, and hexagon are all polygons — closed figures with straight sides. A circle has no straight sides or vertices, making it fundamentally different from the polygons.
Mensa IQ Test Mensa IQ Odd One Out Puzzles 1
Which number does NOT belong in this group: 2, 3, 5, 7, 9, 11, 13?