Can i unreport numbers entered if they are incorrect

It depends.  Generally reporting more income will increase your taxes and reduce any refund. ( There are some exceptions to this, for some credits, etc)

However, you are required to report all income received, including all unreported tips.  

If you have other income to report that was not reported on your W2 or 1099 from your work, you can either request a corrected report from your employer (this is the preferred method) or report it as Other Income:

To enter your other income as other miscellaneous income:

1. Click on the “Federal Taxes” tab ("Personal" tab in TurboTax Home & Business)
2. Choose “Income & Expenses”
3. Choose “I’ll choose what I work on”
4. Scroll down the screen until to come to the section “Less Common Income”
5. Choose "show more", then Miscellaneous Income
6. Choose "Other Reportable Income" 
7. Any miscellaneous income that has not been reported elsewhere can be reported in this manner.