Assignment is the act of changing the value of an existing variable. A variable's value may be changed to any value that is a subtype of the variable's declared type.
The act of assignment is accomplished with the use of an assignment phrase. The expression used in the assignment phrase must evaluate to a subtype of the variable's type.
VARNAME := EXPRESSION
humidityPercent := 50 + 20
NB: These code excerpts show assignment phrases. An assignment statement, like any statement, ends in a semicolon.
References: An in-depth look at assignment phrases