To calculate the annual gross pay, you typically consider the salary and any additional compensation, but from your question, it seems you're only providing Omar's salary and retirement amount.
If Omar's salary is 42,000 and the retirement contribution is separate (like a retirement plan deduction), then the annual gross pay would still be:
Annual Gross Pay = Salary
\[ \text{Annual Gross Pay} = 42,000 \]
Note that the retirement amount might not be included in the gross pay but might be an expense that is deducted from his salary or an employer contribution.
So, if you are only looking for the gross pay based on the salary, his annual gross pay is 42,000.
If you meant something different or have more components to include, please clarify!