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Report a calculation issue

Optional feedback can be sent to yardfill.helpful594@aleeas.com. This is the existing shared public forwarding alias used by the operator's free-tool portfolio, not a dedicated Bookdigit mailbox. It forwards to the operator's private email address; that destination is not published here.

A useful report describes the entered characters, what the tool showed and the result you expected. Include a small example only if you are comfortable sending it by email. The calculator itself does not transmit your entry or attach a diagnostic automatically.

Do not send passwords, account access, identification documents or payment details. There is no paid support or promised response time. Questions about assignment of an ISBN, publisher registration or title metadata belong with the appropriate agency or catalog rather than this arithmetic tool.

You can use the checker without contacting anyone. See privacy for local export and email details.