If you import a file with a file name having the Excel extension (xls or xlsx) then Mathematica will import it as a list structure. The top of the structure is a list containing the worksheets. Inside each worksheet is a list of lists, where each inner list is a row. When importing a spreadsheet, Mathematica will recognize text representing numbers and read them as such. If this doesn't work for you, I suggest you post an example with the Mathematica code in the spikey box and the spreadsheet attached.
data = Import["MySpreadsheet.xlsx"]