If you are talking about order as in PEMDAS, then it is important when you have certain equations.
Example:
20 - 6 • 2 = ?
The answer is 8, because you go start with multiplication then you subtract.
But, if you just went straight across without order you would get 24.
Order is necessary for organized and accurate equations that could affect your answer.
P- parenthesis
E- exponents
M- multiplication
D- division
A- addition
S- subtraction