Assertion: variable | /r/HasProperty | letter
Facets:
value: usually
type: DEGREE
value: in mathematics
type: OTHER
Source sentences:
text: In mathematics, a variable is a symbol or letter, such as "x" or "y," that represents a value.
text: Variables are (usually) letters or other symbols that represent unknown numbers or values.
text: Variables are letters or other symbols that represent unknown numbers or values