less than sign symbol
About less than sign symbol
< is the less than sign symbol, a fundamental mathematical comparison operator used to indicate that one value is smaller than another. The less than sign symbol is one of the most basic and frequently used symbols in mathematics, appearing in arithmetic, algebra, calculus, and virtually every branch of quantitative reasoning. For example, 3 < 5 reads as "three is less than five," and the less than sign symbol points its open end toward the larger value, with the pointed end indicating the smaller quantity.
The less than sign symbol < consists of a pair of diagonal lines meeting at a sharp point on the left, creating an angle that opens toward the right. As a Unicode character officially named LESS-THAN SIGN, the less than sign symbol holds codepoint U+003C within the basic ASCII set, ensuring universal compatibility across all fonts, operating systems, and programming environments. The less than sign symbol is also a critical character in HTML and XML, where it serves as the opening delimiter for tags (e.g., <html>).
【Mathematical Applications】 The less than sign symbol is used in inequalities to express relationships between quantities, such as x < 10 (x is less than 10). In combination with the equals sign, it forms ≤ (less than or equal to). The less than sign symbol is also foundational in number lines, interval notation, and comparative analysis across all STEM fields. Its counterpart, the greater than symbol >, works in tandem with the less than sign symbol to enable comprehensive comparison operations.
【Programming and Markup Use】 Beyond mathematics, the less than sign symbol plays a vital role in computer science: it is used as a comparison operator in programming languages (e.g., if (x < 5)), and as the opening bracket for HTML and XML tags. In some languages, << represents the left shift operator. Because of its dual role in markup and math, the less than sign symbol must be carefully escaped in HTML as < to avoid being interpreted as an opening tag.
How to Type less than sign symbol
Windows Input
Method 1: Press the < key directly on your keyboard (located next to the M key on US keyboards, or with Shift + < on some layouts); Method 2: Hold Alt and type 60 on the numeric keypad; Method 3: Type xiao yu (Chinese pinyin for "less than") in the Microsoft Pinyin input method and look for < in the candidate list.
Mac Input
Method 1: Press the < key directly on your keyboard (on US keyboards, this is the comma key with Shift); Method 2: Press Control + Command + Space to open the Character Viewer and search for "less-than sign".
HTML/CSS Input
HTML: < or < or <; CSS: content: "\003C";
LaTeX Input
In LaTeX math mode, type < directly or use \textless in text mode (requires the amstext package). For proper spacing in math, use < directly, which automatically renders with appropriate spacing around the operator.
less than sign symbol FAQ
What is the difference between the less than sign symbol < and the left angle bracket ⟨?
The less than sign symbol < (U+003C) is a mathematical comparison operator used to indicate inequality. The left angle bracket ⟨ (U+27E8) is a typographic bracket used in mathematical notation to represent inner products, bra-ket notation in quantum mechanics, and sometimes in linguistics. While they look similar, the less than sign symbol has sharper angles and serves a purely comparative function, whereas angle brackets serve as delimiters and grouping symbols.
How do I type the less than sign symbol < on a keyboard without a dedicated < key?
On keyboards without a dedicated less than sign symbol < key, you can: ① On US keyboards, the less than sign symbol is located above the comma key, accessed by pressing Shift + ,; ② On UK keyboards, press Shift + < (next to the Z key); ③ On Windows, hold Alt and type 60 on the numeric keypad; ④ On Mac, the same keyboard shortcuts apply depending on your keyboard layout.
Why do I need to use &lt; in HTML instead of typing < directly?
In HTML, the less than sign symbol < must be written as < because the browser interprets a raw < character as the start of an HTML tag. If you write 3 < 5 directly in HTML, the browser may misinterpret the < as an opening tag and break your page layout. Using the HTML entity < ensures the less than sign symbol displays correctly without being parsed as markup.
What is the Unicode codepoint for the less than sign symbol <?
The Unicode codepoint for the less than sign symbol < is U+003C. Its decimal HTML entity is < and its hexadecimal entity is <. The named HTML entity is <. The less than sign symbol resides in the basic ASCII block and is one of the oldest and most universally supported characters in computing.
What is the mnemonic for remembering the less than sign symbol direction?
A common mnemonic for the less than sign symbol < is that the open side (the "mouth") points toward the larger number, and the closed point indicates the smaller number. Some people remember that the less than sign symbol looks like an 'L' (for "Less") when tilted slightly — the left-pointing tip resembles the letter 'L'. Another popular mnemonic is that the "greedy alligator" always eats the bigger number, so its mouth opens toward the larger value.