If we enter numbers in an Excel cell formatted as text, then these text-type numbers can't be sorted, summed, and so on, even if simply changing the cell format to "numeric" doesn't help, we need to convert them to numeric formats.
Method One
Enter a value of 1 in any blank cell, select the cell, perform the copy operation, and then select the cells (ranges) that you want to convert, perform the edit, paste Selective command, open the Paste Selective dialog box, select the Multiply option, and then make sure you return.
The above methods are available in all versions of Excel.
Method Two
If you are using Excel 2002 or Excel 2003, you can select the cell (range) you want to convert, a smart tag appears next to the cell, click the smart Tag, and then select the Convert to Number option in the Drop-down list that pops up, and you can quickly complete the conversion.