Converting a CSV file edited in Numbers to a TXT File

Is that how you want the final product to look? If you want it to look more tabular and without commas, you might try this:

1. Select the table or the area of the table you want converted.
2. Copy
3. Start up the TextEdit app
4. Format/Make Plain Text (You have to do this before pasting. If afterward you get different results)
5. Paste

Here is an example showing the Numbers table and resulting TextEdit document. Forgive the random text.

Did you try the Numbers menu item "File > Export To… > CSV"?

You can change the name of the file you export from Numbers in the Finder. Single click the name in the Finder, then add ".txt" to the end of the file name.

When I drag a CSV to Pages, I end up with a document that has the same look as the CSV (lots of commas). When I export it to plain text, I get the same CSV but with a TXT extension. Are you getting a tab separated file out of it, like I do with the process using TextEdit?