Aim:how do we evaluate algebraic expressions?

12x                                      4/y                                                    3xy/2

12•x                                    4÷y                                                 3•x•y/2

12(x)                                                                                        3(xy)/2  12*x

   The difference between a Variable and a Constant is that a variable varies with other numbers and a constant remains as the same number and it does not change at all. Moreover, a Constant is a number that cannot change. It cannot change because it is not a variable. A variable is a vary. A vary is the difference or change. Finally, this is the difference between a Variable and Constant.