When completing financial statements, I need to know how to get the totals for the financial statements for three months ending

When completing financial statements, I know how to calculate the totals for each month ending but I am not sure how to calculate the totals for financial statements of two or three months ending. How do I determine the accurate amounts for two or three months ending

It's just the totals of all of them. i.e. you have statements for January, February and March. The 3-months ended in March is all three months totaled together. Now, you can't do this for a Balance Sheet, because those numbers are always balances as of a specific date. You can't total them. But like on the income statement, if Jan had sales revenue of 100,000, February had 140,000 and March had 130,000... then you have a total of 370,000. It just keeps accumulating throughout the year.

If you're doing something in the middle of the year, like April, May and June, same thing, but Jan - March aren't included because that's not the prior 3 months.