Numbers in Everday Life
Number of stickers on a Rubik's Cube
54
rude, unkind / the average
Δ
Delta — Change in a Variable
20% of 250
50
In a right triangle, a² + b² = c²
Pythagorean Theorem
Minutes in a day
1440
reasonable, level-headed / expressible as a fraction
Rational
∑
Sigma — summation
Distinct arrangements of the letters in BAYLOR
720
Differentiation and integration are inverse operations; it lets you evaluate a definite integral using an antiderivative.
Fundamental Theorem of Calculus
Dots on a pair of dice
42
weird / can be written as 2k + 1
Odd
∈
Set membership, "Is an element of"
d/dx (x³ − 5x) when x=1
-2
Any map can be colored with at most four colors so no two regions sharing a border match.
Four Color Theorem
Degrees between two hour marks on a clock face
30
Something you fly in / a two-dimensional surface extending infinitely in all directions
Plane
∂
Partial derivative - del, curly d
Determinant of
[3, 1
4, 2]
2
No positive integers a, b, c satisfy aⁿ + bⁿ = cⁿ for n greater than 2.
Fermat's Last Theorem
Sum of all the numbers on a rack of pool balls
120
a stretch of open land / a set with addition and multiplication that both behave
Field
ℵ
Aleph — Cantor's notation for cardinality of infinite sets
log₂(x) + log₂(x − 2) = 3
x=?
4
No nonvanishing continuous tangent vector field exists on an even-dimensional sphere
Hairy Ball Theorem