custum format cells

How do i use the positive values of the cells in formulas and negative values of the cells in graph. for example. i have a column containing values(7.8.9) and i use these values for formulating other cells, but when i plot these values in graph i need to plot it as(-7,-8,-9). Thanks in advance!

Hi

A solution is to format the Y axis: Check the "Values in reverse order" box and format the labels changing the sign of the numbers.