Left-hand side and right-hand side of an equation

In mathematics, LHS is informal shorthand for the left-hand side of an equation. Conversely, RHS is the right-hand side. Each is solely a name for a term as part of an expression; and they are in practice interchangeable, since equality is symmetric. This abbreviation is seldom if ever used in print; it is very informal.

More generally, these terms may apply to an inequation or inequality. In the inequality case, there is no symmetry. The right-hand side is everything on the right side of a test operator in an expression. Conversely, the left hand side is everything on the left side.

Some examples

In

2a + 5 = a/3,

the term

a/3

is the RHS.

In

x ≤ 10,

just

10

is the RHS.

See also

equal sign, operator.

Syntax

More abstractly, when using infix notation

T*U

the term T stands as the left-hand side and U as the right-hand side of the operator *. This usage is less common, though.