Math symbols by type
Operators do arithmetic: + and −, × and ÷, ± for "plus or minus", and √ for roots. The true minus sign − is a different character from the hyphen - on your keyboard; it lines up with + and looks right in formulas. More on the multiplication and square root pages.
Relations compare values: = and ≠, ≈ for approximately equal, and the inequality symbols < > ≤ ≥. Calculus uses ∑ for sums, ∫ for integrals, ∂ for partial derivatives and ∞ in limits.
Set theory and logic use ∈ (element of), ∪ and ∩ (union and intersection), ∅ (empty set), ∀ (for all), ∃ (there exists) and ∴ (therefore), plus blackboard bold letters like ℝ for the real numbers. Geometry uses ∠ for angles, ⊥ for perpendicular, ∥ for parallel and ≅ for congruent. Need α, β, θ or σ? They are on the Greek letters page.
Keyboard shortcuts for math symbols
On a Mac (US layout), hold Option and press = for ≠, X for ≈, , for ≤, . for ≥, / for ÷, V for √, 5 for ∞, P for π, W for ∑, B for ∫, D for ∂ and J for ∆. Option + Shift + = gives ±.
On Windows, hold Alt and type on the number pad: 241 for ±, 242 for ≥, 243 for ≤, 246 for ÷, 247 for ≈, 251 for √, 236 for ∞, 227 for π and 0215 for ×. The code table further down this page lists the Unicode and HTML codes for every single symbol shown here.
Writing math in Word, Google Docs and LaTeX
In Microsoft Word, press Alt + = to insert an equation, then type commands like \sqrt, \infty or \pi followed by a space. In Google Docs, choose Insert > Equation and use the same kind of backslash commands, or Insert > Special characters to search for a symbol by name.
LaTeX is the standard for math papers: \times, \div, \pm, \neq, \approx, \leq, \geq, \sqrt{x}, \infty, \sum and \int cover most everyday needs. In code and spreadsheets, stick to plain keyboard characters: * for ×, / for ÷, <= and >=, and != or <> for ≠.