Reporting part-time earnings while on benefits - first time posting

I work some days through a staffing agency while still certifying. There are 8 people counting on me, so I am trying to be careful. The form asks for gross earnings, which I do not see until later. Who can I ask without risking my claim?

I estimated and then checked my pay stub. When there was a small difference I wrote to the agency to correct it.

Report honestly and keep your stubs. An honest small error is much easier to fix than a missing report.