Useful mathematical/scientific characters
Name
 Symbol
 Encoding

Degrees
 °
 °

Prime
 ′
 ′

Double prime
 ″
 ″

Square root
 √
 √

Cube root
 ∛
 ∛

Plus or minus
 ±
 ±

Product
 ×
 ×

Dot operator
 ⋅
 ⋅

Circle operator
 ∘
 ∘

Direct sum
 ⊕
 ⊕

Congruent to
 ≡
 ≡

Not congruent to
 ≢
 ≢

Asymptotic to
 ∼
 ∼

Approximately equal
 ≈
 ≈

Less than approx.
 ≲
 ≲

Greater than approx.
 ≳
 ≳

Isomorphic to
 ≅
 ≅

Proportional to
 ∝
 ∝

Much greater than
 ≫
 ≫

Much less than
 ≪
 ≪

Member of
 ∈
 ∈

Not member of
 ∉
 ∉

Intersection
 ∩
 ∩

Union
 ∪
 ∪

Contained in
 ⊆
 ⊆

Not contained in
 ⊈
 ⊈

Strictly contained in
 ⊂
 ⊂

Contains
 ⊇
 ⊇

Doesn't contain
 ⊉
 ⊉

Strictly contains
 ⊃
 ⊃

Repeated sum
 ∑
 ∑

Repeated product
 ∏
 ∏

Integral
 ∫
 ∫

Gradient
 ∇
 ∇

Divides
 ∣
 ∣

Doesn't divide
 ∤
 ∤

Double vertical bars
 ∥
 ∥

Maps to
 →
 →

Element maps to
 ↦
 ↦

Bidirectional arrows
 ⇄
 ⇄

If and only if
 ⇔
 ⇔

Infinity
 ∞
 ∞

Planck's constant
 ℎ
 ℎ

Planck's constant / 2π
 ℏ
 ℏ

Circled dot
 ⊙
 ⊙

Weierstrass P
 ℘
 ℘

Cyrillic Sha (capital)
 Ш
 Ш

Complex numbers
 ℂ
 ℂ

Quaternions
 ℍ
 ℍ

Natural numbers
 ℕ
 ℕ

Projective space
 ℙ
 ℙ

Rational numbers
 ℚ
 ℚ

Real numbers
 ℝ
 ℝ

Integers
 ℤ
 ℤ
