Less than sign (<)

How to read it

It is read “is less than”: OpenStax’s Prealgebra reads a < b as “a is less than b”, which puts a to the left of b on the number line. Swapping the two sides turns it into the greater than sign: 7 < 11 says the same as 11 > 7. The sign is the keyboard character U+003C, LESS-THAN SIGN, and Unicode notes its second job, paired with >, as the angle brackets of computer markup.

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Telling < from >

The point of < faces the smaller number and the open side the larger one; OpenStax’s Prealgebra says “the smaller side of the symbol faces the smaller number”. The well-known reading aid makes the open side a hungry mouth, as in a 2024 PBS Let’s Learn lesson where the sign is a gator whose mouth points at the side with more.

The angle sign ∠

Geometry’s angle sign ∠ (U+2220) began as <. Cajori’s history records that Pierre Hérigone adopted < for an angle in 1634, three years after Harriot’s book used it for “less than”. Harriot’s meaning won and the angle sign was changed, though < for an angle kept turning up in books of the seventeenth and eighteenth centuries.

Other look-alikes

The less than or equal to sign ≤ has a line under the <. Unicode separates < from the modifier letter left arrowhead ˂ (U+02C2), the single left-pointing angle quotation mark ‹ (U+2039), and the angle brackets 〈 (U+2329) and ⟨ (U+27E8).