HTML Entity for Double Struck N-Ary Summation (⅀)
What You'll Learn
How to display the Double Struck N-Ary Summation (⅀) in HTML using hexadecimal, decimal, and CSS escape methods. This character is U+2140 (DOUBLE-STRUCK N-ARY SUMMATION) in the Letterlike Symbols block (U+2100–U+214F)—used in mathematics for n-ary summation (sum over indices).
Render it with ⅀, ⅀, or CSS escape \2140. There is no named HTML entity for U+2140. For regular summation use ∑ or ∑ (∑, U+2211). See also math entities.
⚡ Quick Reference — Double Struck N-Ary Summation
U+2140Letterlike Symbols block
⅀Hexadecimal reference
⅀Decimal reference
—Not available for U+2140
Name Value
──────────── ──────────
Unicode U+2140
Hex code ⅀
HTML code ⅀
Named entity —
CSS code \2140
Related U+2211 = Summation (∑)Complete HTML Example
This example demonstrates the Double Struck N-Ary Summation (⅀) using hexadecimal code, decimal HTML code, and a CSS content escape. There is no named HTML entity:
<!DOCTYPE html>
<html>
<head>
<style>
#point:after{
content: "\2140";
}
</style>
</head>
<body>
<p>Double Struck N-Ary Summation using Hexadecimal: ⅀</p>
<p>Double Struck N-Ary Summation using HTML Code: ⅀</p>
<p id="point">Double Struck N-Ary Summation using CSS Entity: </p>
</body>
</html>🌐 Browser Support
U+2140 is widely supported in modern browsers when rendered with a font that includes Letterlike Symbols:
👀 Live Preview
See the Double Struck N-Ary Summation (⅀) in mathematical notation:
🧠 How It Works
Hexadecimal Code
⅀ uses the Unicode hexadecimal value 2140 to display the Double Struck N-Ary Summation. The x prefix indicates hexadecimal format.
Decimal HTML Code
⅀ uses the decimal Unicode value 8512 to display the same character.
CSS Entity
\2140 is used in CSS stylesheets, particularly in the content property of pseudo-elements like ::before and ::after.
Same visual result
All three methods produce: ⅀. Unicode U+2140. Regular summation: ∑ (∑, U+2211). No named entity for U+2140.
Use Cases
The Double Struck N-Ary Summation (⅀) commonly appears in:
Mathematics where ⅀ denotes an n-ary sum over indices, series notation, or summation in double-struck style.
Sum over natural numbers (ℕ) or over a set in formal definitions and proofs using letterlike symbols.
Textbooks, papers, and course materials requiring letterlike math symbols in HTML.
Equation editors and math rendering alongside other double-struck italic letters.
Entity lists and guides for Letterlike Symbols (U+2100–U+214F).
Use math-capable fonts so ⅀ renders clearly for all readers.
💡 Best Practices
Do
- Use
⅀or⅀for ⅀ - Use math fonts (Cambria Math, STIX Two Math) for reliable rendering
- Distinguish ⅀ (n-ary) from ∑ (
∑, regular summation) - Use
\2140only inside CSScontent - Keep entity style consistent across the document
Don’t
- Assume a named entity exists for U+2140—it does not
- Use
∑when you need regular ∑, not n-ary ⅀ - Put CSS escape
\2140in HTML text nodes - Forget UTF-8 (
<meta charset="utf-8">) on math pages - Assume every font includes Letterlike Symbols
Key Takeaways
No named entity—use numeric references
⅀ ⅀For CSS stylesheets, use the escape in the content property
\2140Unicode U+2140 DOUBLE-STRUCK N-ARY SUMMATION
Regular ∑: U+2211 via ∑ or ∑
Three methods, one glyph — widely supported in modern browsers
❓ Frequently Asked Questions
⅀ (hex), ⅀ (decimal), or \2140 in CSS content. All produce ⅀. There is no named HTML entity for U+2140.U+2140 (DOUBLE-STRUCK N-ARY SUMMATION). Letterlike Symbols block (U+2100–U+214F). Hex 2140, decimal 8512. N-ary summation (sum over indices).⅀ or ⅀) go in markup. The CSS escape \2140 is used in stylesheets, typically in the content property of pseudo-elements.ⅈ, ⅆ). U+2140 does not. Use ⅀, ⅀, or \2140. For regular summation use ∑ (U+2211, ∑).Explore More HTML Entities!
Discover 1500+ HTML character references — math symbols, letterlike glyphs, and more.
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