Just learned this last week: if it's a really simple conversion, you can actually do it from the data grid. With the data grid open, unprotect the data (edit menu in EG 4.2... this might have been the data menu in EG 4.1), right-click on the column header and select Properties. Under type, you can pick Character or Numeric and it will attempt conversion after warning you that you can't go back once the conversion is complete. You do get a preview of what the conversion will look like, which gives you one last chance to back out.
As Doc mentioned, the Query Builder with functions like PUT and INPUT offers a much more robust set of tools for doing data conversion.