How do you change all positive numbers in a spreadsheet to negatives?

To change all positive numbers in a spreadsheet to negatives, you can use a simple formula. In Excel or google Sheets, you can create a new column and use the formula =IF(A1>0, -A1, A1) where A1 is the cell with the original number. Drag the formula down to apply it to the entire column. Alternatively, you can multiply the entire range of positive numbers by -1 to convert them to negatives.