Algebra: a type of math in wich letters or symbols are used to represent unknown parts of an expression or equation
Variable: an unknown part
Variable Expression: a problem with a variable and NO equal sign
Variable Equation: a problem witha variable AND an euqal sign
23 - x = 18 x is the variable
2 + 8 + n = 21 n is the variable
Sally has 21 unread text messages 13 were from her best friend Taylor.
13 + x = 21