OFFSET for a trailing 12-month sum

Trailing 12-month reporting is a common way to smooth out seasonality and focus on the latest full year of performance. In real dashboards, this helps totals and averages stay current as each new month is appended.

In this exercise, you will use OFFSET to return a 12-row revenue window that always ends at the latest month in the table.

=OFFSET(reference, rows, cols, [height], [width])

Here, the key idea is to count how many revenue rows exist, move down to the first month in the trailing window, and then return a positive-height range that spans 12 rows.

Your task

1. Review the monthly revenue table in A1:B19.
2. In E2, calculate the trailing 12-month revenue total using a 12-row OFFSET range that ends at the latest month in the table.
3. In E3, calculate the trailing 12-month revenue average using AVERAGE over that same 12-row OFFSET range.

Use full-column counts such as COUNTA(B:B) so the summary can keep working as new revenue rows are appended below the current table.

When you are done, the summary section in D1:E3 should update from the latest 12 months in the table rather than a fixed hard-coded range.