Hi Polley,
We do not allow merging on number element , for example if you merge numbers 564 987 and 546 in a comma separated list it will evaluate to
564,987,546 which looks like a large number and not a list, which can be miss leading.
As a solution you can add a text-box on the form and promote this textbox as solution field, in your repeating table number field you can apply a rule to concat all the numbers separated by a unique separator.
I have attached a test solution here : https://nowtransfer.de/b2b72d75e5ee
The result will look like :

You can further remove textbox_5 from the form and make it as hidden as per requirement.
Hope this helps.
Regards
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Hammad Naeem
Precisely Software Inc.
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