As

illogical as it may seem, calculators have two major types of logic which change the results you may get from inputting several
numbers.

The first kind of calculator logic is

Serial Logic.

That is, the calculator will operate all terms serially.

The arguments 3 + 3 * 5 = will return 45 on a Serial Logic Calculator, because the calculator only handles
two numbers at once. It treats it as such: 3 + 3 equals 9. New Problem, first argument 9. 9 * 5 = 45.

This would be incorrect in

algebra if the problem was "3 + 3 * 5 = x (What is x?)" because that would not follow

The Order of Operations, which when applied here states that,

multiplication takes place before

addition. Therefore, with a
serial logic

calculator, you must follow the order of operations yourself,

multiplying 3 * 5 first then adding 3.

On an algebraic logic calculator, imputting the string of arguments 3 + 3 * 5 = will return 18, because the

algebraic logic
calculator treats all numbers as part of the same

expression.