Answer :

littlestar
basically variable is a term that specifies unspecified numbers..
variable expression:
                           it is the algebraic expression in which both numbers and variables are comprised by means of arithmetic operations 
example:
1) 2a + 3
2) 5/2 - x 
TheBlueFox

In mathematics, a variable expression is an expression that contains operations, numbers, and variables.

For example, if I have 6 coins in my pocket in . addition to the number of coins that are in my jar at home, then then the total number of coins would be represented as X + 6.

X would represent the unknown amount of coins in my jar at home.

This would be a variable expression because it contains an operation "addition", a number "4", and a variable "X."