Math Trivia Questions

53 math questions, from ★ easy to ★★★★★ hard. Tap Show answer for the answer and source.

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What is 12 + 15? ★
- 28
- 37
- 25
- 27
Show answer
27 — 12 + 15 = 27.
How many things are in a dozen? ★
- 10
- 6
- 20
- 12
Show answer
12 — A dozen is a group of twelve. Source: Wikipedia 'Dozen'
What is 9 × 6? ★
- 45
- 63
- 56
- 54
Show answer
54 — 9 × 6 = 54.
How many metres are in one kilometre? ★
- 100
- 10,000
- 10
- 1,000
Show answer
1,000 — One kilometre equals 1,000 metres. Source: Wikipedia 'Kilometre'
What number does the Roman numeral X stand for? ★
- 50
- 100
- 5
- 10
Show answer
10 — In Roman numerals, X = 10 (V = 5, L = 50, C = 100). Source: Wikipedia 'Roman numerals'
What is half of 50? ★
- 20
- 15
- 30
- 25
Show answer
25 — 50 ÷ 2 = 25.
What is 100 − 37? ★
- 73
- 53
- 67
- 63
Show answer
63 — 100 − 37 = 63.
Which of these numbers is even? ★
- 9
- 15
- 7
- 14
Show answer
14 — 14 can be divided by 2 with no remainder, so it is even.
A triangle has three sides. ★
- True
- False
Show answer
True — A triangle is a polygon with three sides and three corners. Source: Wikipedia 'Triangle'
7 × 8 = 54. ★
- True
- False
Show answer
False — 7 × 8 = 56.
What number does the Roman numeral C stand for? ★★
- 50
- 500
- 10
- 100
Show answer
100 — In Roman numerals C = 100 (X = 10, L = 50, D = 500). Source: Wikipedia 'Roman numerals'
What number is the Roman numeral IX? ★★
- 11
- 19
- 4
- 9
Show answer
9 — IX means one less than ten, which is 9. Source: Wikipedia 'Roman numerals'
How many sides does a pentagon have? ★★
- 6
- 7
- 8
- 5
Show answer
5 — A pentagon is a polygon with five sides. Source: Wikipedia 'Polygon'
How many degrees are in a right angle? ★★
- 45
- 180
- 360
- 90
Show answer
90 — A right angle is exactly 90°, a quarter of a full turn. Source: Wikipedia 'Right angle'
Which of these numbers is prime? ★★
- 9
- 21
- 15
- 13
Show answer
13 — 13 can only be divided by 1 and 13; 9, 15 and 21 have other factors. Source: Wikipedia 'Prime number'
What is 15% of 200? ★★
- 20
- 45
- 15
- 30
Show answer
30 — 200 × 0.15 = 30.
What is 12 × 12? ★★
- 142
- 154
- 124
- 144
Show answer
144 — 12 × 12 = 144.
1 is a prime number. ★★
- True
- False
Show answer
False — A prime must be greater than 1, so 1 is not prime. Source: Wikipedia 'Prime number'
2 is the only even prime number. ★★
- True
- False
Show answer
True — Every even number bigger than 2 can be divided by 2, so it is not prime. Source: Wikipedia 'Prime number'
A hexagon has eight sides. ★★
- True
- False
Show answer
False — A hexagon has six sides; an octagon has eight. Source: Wikipedia 'Polygon'
The three angles inside a triangle add up to 180 degrees. ★★
- True
- False
Show answer
True — The interior angles of any triangle always total 180°. Source: Wikipedia 'Polygon'
An obtuse angle is smaller than a right angle. ★★
- True
- False
Show answer
False — An obtuse angle is larger than 90°; an acute angle is smaller. Source: Wikipedia 'Right angle'
A cube has 8 faces. ★★
- True
- False
Show answer
False — A cube has 6 faces, 12 edges and 8 corners (vertices). Source: Wikipedia 'Cube'
What is the sum of the interior angles of a hexagon? ★★★
- 540°
- 900°
- 360°
- 720°
Show answer
720° — For n sides the sum is (n − 2) × 180°, so (6 − 2) × 180° = 720°.
How many sides does a dodecagon have? ★★★
- 10
- 20
- 8
- 12
Show answer
12 — A dodecagon is a 12-sided polygon. Source: Wikipedia 'Dodecagon'
What is the next prime number after 31? ★★★
- 33
- 35
- 39
- 37
Show answer
37 — 33 = 3×11, 35 = 5×7 and 37 has no divisors except 1 and itself.
What is 2 to the power of 10? ★★★
- 2,048
- 1,000
- 512
- 1,024
Show answer
1,024 — Doubling 2 ten times gives 1,024.

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What is a triangle with all three sides of different lengths called? ★★★
- Isosceles
- Equiangular
- Equilateral
- Scalene
Show answer
Scalene — Scalene triangles have no equal sides. Source: Wikipedia 'Triangle'
What number does the Roman numeral L stand for? ★★★
- 500
- 1,000
- 100
- 50
Show answer
50 — In Roman numerals L = 50, C = 100, D = 500 and M = 1,000. Source: Wikipedia 'Roman numerals'
The number 1 is a prime number. ★★★
- True
- False
Show answer
False — A prime must be greater than 1, so 1 is not prime. Source: Wikipedia 'Prime number'
A square is a special kind of rectangle. ★★★
- True
- False
Show answer
True — A square is a rectangle whose four sides are all the same length. Source: Wikipedia 'Rectangle'
The area of a circle equals pi times the radius squared. ★★★
- True
- False
Show answer
True — The area of a circle with radius r is πr². Source: Wikipedia 'Area of a circle'
The four angles inside any quadrilateral add up to 360 degrees. ★★★
- True
- False
Show answer
True — A quadrilateral splits into two triangles of 180° each, so 2 × 180° = 360°.
How many faces does a regular icosahedron have? ★★★★
- 12
- 8
- 30
- 20
Show answer
20 — An icosahedron has 20 triangular faces, 30 edges and 12 vertices. Source: Wikipedia 'Regular icosahedron'
What is a polygon with nine sides called? ★★★★
- Decagon
- Heptagon
- Octagon
- Nonagon
Show answer
Nonagon — A nonagon, also called an enneagon, has nine sides. Source: Wikipedia 'Nonagon'
One radian is approximately how many degrees? ★★★★
- 90°
- 3.14°
- 45°
- 57.3°
Show answer
57.3° — One radian is 180°/π, about 57.3 degrees. Source: Wikipedia 'Radian'
What is the square root of 289? ★★★★
- 13
- 19
- 27
- 17
Show answer
17 — 17 × 17 = 289.
What is 7! (7 factorial)? ★★★★
- 720
- 49
- 40,320
- 5,040
Show answer
5,040 — 7! = 7 × 6 × 5 × 4 × 3 × 2 × 1 = 5,040.
In the sequence 1, 1, 2, 3, 5, 8…, what is the 10th number? ★★★★
- 34
- 45
- 89
- 55
Show answer
55 — Each number is the sum of the two before it: …21, 34, 55.
What is the smallest prime number greater than 90? ★★★★
- 91
- 99
- 93
- 97
Show answer
97 — 91 = 7 × 13, 93 = 3 × 31, 95 = 5 × 19, so the next prime is 97.
What is the decimal number 13 written in binary? ★★★★
- 1011
- 1001
- 1110
- 1101
Show answer
1101 — 13 = 8 + 4 + 1, which is 1101 in binary.
Zero is an even number. ★★★★
- True
- False
Show answer
True — Zero is even because it equals 2 × 0. Source: Wikipedia 'Parity of zero'
The number 1 is the smallest prime number. ★★★★
- True
- False
Show answer
False — 1 is not prime; the smallest prime is 2, the only even prime. Source: Wikipedia 'Prime number'
Pi is exactly equal to 22/7. ★★★★
- True
- False
Show answer
False — Pi is irrational, so 22/7 is only an approximation. Source: Wikipedia 'Pi'
Every square is also a rhombus. ★★★★
- True
- False
Show answer
True — A rhombus has four equal sides, so a square is a rhombus with right angles. Source: Wikipedia 'Rhombus'
The interior angles of a hexagon add up to 720 degrees. ★★★★
- True
- False
Show answer
True — The angle sum is (n − 2) × 180°, so (6 − 2) × 180° = 720°.
A googol is 10 to the power of 1,000. ★★★★
- True
- False
Show answer
False — A googol is 10 to the power of 100: a 1 followed by 100 zeros. Source: Wikipedia 'Googol'
Who proved Fermat's Last Theorem, published in 1995? ★★★★★
- Grigori Perelman
- John Nash
- Terence Tao
- Andrew Wiles
Show answer
Andrew Wiles — Andrew Wiles's proof was published in the Annals of Mathematics in 1995. Source: Wikipedia 'Fermat's Last Theorem'
What is the smallest perfect number? ★★★★★
- 12
- 10
- 28
- 6
Show answer
6 — 6 equals the sum of its proper divisors: 1 + 2 + 3. Source: Wikipedia 'Perfect number'
What is the value of 0! (zero factorial)? ★★★★★
- Undefined
- Infinity
- 0
- 1
Show answer
1 — By the empty-product convention, 0! = 1. Source: Wikipedia 'Factorial'
According to Euler's identity, what does e^(iπ) equal? ★★★★★
- 1
- 0
- i
- −1
Show answer
−1 — Euler's identity is e^(iπ) + 1 = 0, so e^(iπ) = −1. Source: Wikipedia 'Euler's identity'
Pi was proven to be a transcendental number in the 19th century. ★★★★★
- True
- False
Show answer
True — Ferdinand von Lindemann proved pi is transcendental in 1882. Source: Wikipedia 'Pi'
There are exactly five Platonic solids (regular convex polyhedra). ★★★★★
- True
- False
Show answer
True — Only the tetrahedron, cube, octahedron, dodecahedron and icosahedron qualify. Source: Wikipedia 'Platonic solid'