Salesforce Shift Time Formulas

My current Salesforce report lists every user’s first login, final logout, and each time they punch a break. What it still lacks is the math behind it. I need row-level and summary formulas that: • show... (Budget: ₹600 - ₹1500 INR, Jobs: Business Analysis, Data Analysis, Data Management, Excel, QlikView, Report Writing, Salesforce App Development, Salesforce.com)