Hello, thank you for taking the time to post your question!
My guess is that it’s wanting you to compute how many checks that you processed per hour, so like the rate at which you are processing the checks. To do that you want to take
Total Checks / Total Hours
=6644 / 4
=1661 checks per hour
You could also find mistakes per check or checks processed per mistake as well with the information given using a similar process! It just depends on what exactly the question was asking about
I hope that helps get you moving in the right direction! Feel free to reach out if you have any additional questions beyond that :)