Arithmetic operations with dates

In this exercise, you will perform arithmetic operations on dates in two different ways: using the arithmetic operators ("+" and "-") and also using the DATEDIFF() function. You will use these variables:

DECLARE @date1 datetime = '2018-12-01';
DECLARE @date2 datetime = '2030-03-03';

Create a SELECT statement, in which to perform the following operations:

• Subtract @date1 from @date2.
• Add @date1 to @date2.
• Using DATEDIFF(), calculate the difference in years between the results of the subtraction and the addition above.

What is the result returned by the DATEDIFF() function?