Assuming you have a list of jobs and the dates they were completed on in an Excel spreadsheet, you can use a simple COUNTIF function to count the number of jobs completed on a specific date.

For example, let's say your data is in cells A1:B500, with job completion dates in column B. To count the number of jobs completed on January 1st, you would use the following formula:

=COUNTIF(B1:B500,"1/1/2018")

This would give you a count of all the jobs completed on January 1st, 2018. You can change the date in the formula to count jobs completed on any other date.