For example, you might need to calculate only the number of checks over a certain dollar amount or paychecks related to particular people. In these cases, you'll need to use COUNTIF and COUNTIFS.

We show you how to use Excel to count days between two dates using the DAYS, DATEDIF, NETWORKDAYS, and TODAY functions, and Subtraction.

The article How to calculate conditional subtotals in an Excel revenue sheet uses simple expressions, a function, and a conditional format to display a daily balance in a revenue sheet.