Greetings, @judy47.
Congrats on making your first post here in the Community. I hope your day is going well so far.
After trying this in my test account, I was able to add a decimal in the "Account Number" field for an account. However, there isn't a limit of seven digits in the "Account Number" field. You can enter more than seven numbers. Let's try it out with the steps below.
- Go to the Accounting tab on the left-hand menu bar.
- Choose the Chart of Accounts portion.
- Locate the account and click the View Register drop-down menu in the "Action" column.
- Select the Edit option.

5. In the "Number" box, type in the number with a decimal.
6. Once you're done, press the Save and Close button.

Here's an article that can give some additional details about using account numbers in your chart of accounts. For future reference, you can cruise on over to this link about reconciling an account or our tutorials page within the Community.
By doing the instructions above, you'll be able to add a decimal within the account number for your chart of accounts. If you have any other questions or concerns, please don't hesitate to ask. The Community is always here to have your back. Have a splendid day!