Combinatorics
Algebra
Number Theory
Geometry
People & Trivia
100
The probability of flipping two fair coins and having them both land on heads.
What is 1/4?
100
The minimum number of 12 oz cans needed to provide a gallon (128 ounces) of soda.
What is 11?
100
The number of positive integer prime numbers less than 10.
What is 4?
100
The largest possible integer degree measure of an angle of a triangle.
What is 179?
100
This person has a theorem named after him; this theorem regard the relationship between the lengths of the three sides of a right triangle
Who is Pythagoras?
200
The probability of picking 2 blue balls when drawing two balls (at the same time) from a bag of 3 blue balls and 4 red balls.
What is 1/7?
200
For each pair of real numbers 
, define the operation 
as
.
What is the value of 
?
What is 0
200
The number of factors 2020 has.
What is 12?
200
The number of sides of a regular polygon that has sum of all angle measures as 900 degrees.
What is 7?
200
It is rumored that this person was asked by his primary school teacher to sum up all the numbers from 1 to 100, and later earned a method in his name for summing sequences of numbers.
Who is Gauss?
300
The number of ways to seat 5 people such that two people, Andy and Betty, don't sit next to each other.
What is 72?
300
The infinite sum:
1 + 1/2 + 1/4 + 1/8 + 1/16 ...
What is 2?
300
The sum of the digits of the square of 111,111,111
81
300
Four congruent rectangles are placed as shown. The area of the outer square is 4 times that of the inner square. What is the ratio of the length of the longer side of each rectangle to the length of its shorter side?
What is 3?
300
This formula is named after Hero of Alexandria, and it gives the area of a triangle from three sides.
What is Heron's Formula?
400
The number of ways there are to pick a leadership committee of 4 members and then designate two captains from a group of 6 people.
What is 90?
400
The sum:
1 + 2 + 4 + 8 + 16 + 32 + 64 + 128 + 256
What is 511?
400
The modular inverse of 12 in modulus 19.
(In other words, what is the smallest positive integer x such that 12x leaves a remainder of 1 when divided by 19)
What is 8?
400
Three one-inch squares are placed with their bases on a line. The center square is lifted out and rotated 45 degrees, as shown. Then it is centered and lowered into its original location until it touches both of the adjoining squares. How many inches is the point 
from the line on which the bases of the original squares were placed?
What is 
?
400
This man is most famous for his formula eiπ + 1 = 0. He was also first to introduce the notation for a function f(x).
Who is (Leonhard) Euler?
500
The coefficient of x4 in the expansion of (3x + 2)5
What is 810?
500
The pair of positive integers (a,b) that satisfies the equation:
ab + 4b = 24 - 6a
What is (2,2)?
500
The second smallest positive integer x such that:
x = 3 (mod 5)
x = 5 (mod 7)
(In other words, what is the second smallest positive integer x such that x has a remainder of 3 when divided by 5 and x has a remainder of 5 when divided by 7)
What is 68?
500
The degree measure of an angle of a regular dodecagon (12 sides).
What is 150 degrees?
500
This many digits of pi have been calculated.
What is 62.8 trillion?