How do you know the correct order in which to evaluate algebraic expressions?

In solving algebraic expressions, there is an order in which to solve it.

1) perform the operation inside the parenthesis first  
2) then perform the operation with the exponents
3) apply multiplication and division from left to right of the equation.
4) apply addition and subtraction from left to right of the equation.

Remember this: PEMDAS for easier recall. (parenthesis, exponents, multiplication, division, addition, subtraction)

To evaluate algebraic expressions there is no order. You just need to follow something called pemdas. The way to remember this is
 
p = please
e = excuse
m = my
d = dear
a= aunt
s = sally
 
So just remember Please excuse my dear aunt sally or pemdas.
   
P = parentheses (Apply from left tor right)
E = exponent (Apply from left tor right)
M = multiplication (Apply from left tor right)
D = division (Apply from left tor right)
A = addition (Apply from left tor right)
S = subtraction (Apply from left tor right)
 
Then solve!
 
Hope this helps!! xD