 Sometimes to solve a problem we have to form a mathematical equation.
 A letter or a text string is used to denote an unknown quantity while forming an equation.
 The unknown quantity is called a variable.
 The equation may be solved to find the value of the variable.
Example:
a  5 = 10
While solving an equation, the variables are kept on one side and the numbers are transferred to the other side of the equation.
So adding 5 to both sides we get,
a  5 + 5 = 10 + 5
so we get a = 15
Note: If we perform any operation on one side of the equation, the same operation should be performed on the other side of the equation as well.
Directions: Find the value of the variable in each question and show your work. Also write at least 10 examples of your own involving the operations: addition and subtraction.
