mac numbers NEGATIVE TO POSITIVE

You could do it with a script but that might be the hard way depending on what you need to do. If it is a column of numbers and you want them all positive, insert a new column next to it and use the ABS function. Then select all the cells in that new column, Copy, and Paste Formula Results back to the original column. Finish by deleting the new column.

Then you really should not be thinking about a script.

I can only give a general idea of how to do it. I assume you know how to select cells, create formulas, copy/paste, and do the basic things.

If your original column is column C,

1. Insert a new column to the right of it. This new column will become column D.
2. In column D, the formula will be =ABS(C)
3. Put that formula in all the cells in the column. The results of these formulas should be the positive versions of the numbers in column C. It is the Absolute Value function which turns negatives into positives and leaves positives as positives..
4. Select the cells in column D.
5. Copy
6. Paste Formula Results to Column C (you can find that command in the Edit menu)
7. Delete column D, it is no longer needed.