You can separate numbers ... comma. Both the Delimited and Fixed Width conversion options give you an opportunity to format each column before you convert the data. The options include General ...

The import feature in Numbers ... text-editing programs can let you easily fix a CSV or TSV file to prevent the loss of leading zeroes. Those patterns above say “find any number between commas ...

On the other hand, we often receive data from a foreign source that should be stored as a number, but it stored as text at the source. When this happens, we must convert that text into numbers ...