Cash Flow & Profit Lesson Question

Hey there, I just completed the Cash Flow & Profit lesson, and my question is: How exactly do I determine my revenue minus profit, equals expenses formula when I’m still “in the year” and I don’t have a total revenue number yet? Would it make sense to use last year’s total revenue and expenses to budget the current year? Or … look at the last quarter and base the coming quarter on what I have left after revenue to budget expenses?

Thanks for your help 🙂