Once you have entered a number in response to one question, can that number be blocked so that you cannot answer another question with the same number

Hello,

If I'm understanding your question correctly, so your condition will be based on the answer given by the user, such as from options of giving numbers 1-9, they can only enter such value once and they shall be prevented from entering the same value on a different question. 

Unfortunately, I could not find a solution on how to make this happen within JotForm's limits. I'm theorizing however that this can be possible when you get your form's full HTML source code, place the code on a web page and modify the code there to run such look-up/validation.

If I misunderstood your question or you would like to proceed with this idea, please let us know. 

Thanks.