Use PEMDAS. (Multiplication & divison + addition & subtraction are not in order, solve it from left to right)
Parentheses
Exponents
Multiplication
Division
Addition
Subtraction
23 + 5 × 10 ÷ 2 - 33 + (11 - 8)
Do the parentheses first.
23 + 5 × 10 ÷ 2 - 33 + (3)
Now do multiplication since its first when you read the problem from left to right.
23 + 50 ÷ 2 - 33 + 3
Use division.
23 + 25 - 33 + 3
Now you can solve from left to right.
48 - 33 + 3
15 + 3
18
Using the order of operations, the expression can be simplified to 18.