ℤ
ℤ Set of Integers Symbol
ℤ is the set of all integers — the whole numbers together with their negatives and zero. The Z is from the German Zahlen, “numbers”.
Also known as: integers symbol, set of integers, double struck z, blackboard bold z.
Codes
| Symbol | ℤ | |
| Unicode | U+2124 | |
| HTML entity (named) | ℤ | |
| HTML entity (decimal) | ℤ | |
| HTML entity (hex) | ℤ | |
| CSS | \2124 | |
| LaTeX | \mathbb{Z} | |
| Windows Alt code | Alt + 8484 |
How to type ℤ (Set of Integers Symbol)
Windows2124, Alt + X
In Word, type 2124 then press Alt + X. Elsewhere, copy ℤ above or use Character Map (search “double-struck”).
Mac
No default keystroke. Open Character Viewer (Control + Cmd + Space) and search “double-struck capital Z”, or copy ℤ above.
Microsoft Word2124, Alt + X
Type 2124, then press Alt + X to convert it to ℤ.
Google Docs
Insert → Equation, then type \Z or \mathbb followed by Z. Insert → Special characters and searching “double-struck” also works.
LaTeX\mathbb{Z}
Use \mathbb{Z} in math mode. It needs amssymb or amsfonts — \mathbb is not in core LaTeX.
Usage
- ℤ = {…, −2, −1, 0, 1, 2, …}. Every natural number is an integer, so ℕ ⊂ ℤ ⊂ ℚ ⊂ ℝ.
- n ∈ ℤ is how you say “n is an integer” — the standard way to constrain a variable in an equation or a proof.
- Common decorations: ℤ⁺ for the positive integers, ℤ⁻ for the negatives, and ℤ/nℤ for the integers modulo n.
- Which one to use: ℤ (U+2124) is the ready-made double-struck character. A bold or outlined ordinary Z is not the same character and will not match a search for ℤ — in LaTeX, always write \mathbb{Z} rather than \mathbf{Z}.