Why i am not able to change the text to number? Pls help.

[alycerainbow]

Referring to my excel attachment, column B, C and D are text. I have tried to change them to "General", "Number" and even "Custom", but they still remain as Text. Therefore, i got #value! when i enter formula for calculation in column E. Pls help.

[AranDG]

Unfortunately Excewl has a habit of doing this when data is pasted in / imported in text format, easiet way I've found is either highlight the data that's stored as text and scroll so that you can see the first cell in the data range, hover over the exclamation point that appears next to your data range and select 'Convert to Number'.
This method won't fix any future imports etc though. I've always found multiplying your number stored as text by 1 usually works so try changing your formula to =D3*1*80%. Worked for me on the workbook you attached.

[Kamboj]

Just select from B2 to D61 and change as number