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Hi Courtney,
For your concern, you can use this setup:
- Select the range you want to check. As an example, I select range A1:A10
- Go to Data > Data Validation > under Allow, choose Custom from the drop-down menu
- Paste this formula
=AND(LEN(A1)=7,LEFT(A1,1)="8",SUMPRODUCT(--ISNUMBER(--MID(A1,ROW($1:$7),1)))=7)(Note: change the cell based on the start cell of your select range. For example: if choosing B5:B20, replace A1 with B5)
- If you want an error message when inputting wrong value, you can go to Error Alert and set up the error message as you prefer. After finished, press OK. You can use or adapt my message as well:
As a demonstration on how it will work:
Please try these steps and let me know whether it meets your need. If not, please feel free to reach out again in the comments on this post. I'm happy to assist you further
Thank you for your understanding and cooperation. I'm looking forward to your reply.
If the answer is helpful, please click "Yes" and kindly upvote it.
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