To ignore all numbers stored as text, you need to open the Data tab and select the Text to Columns option. Then, select the Delimited option from the Convert Text to Columns wizard.

Mary Ann Richardson explains that when concatenating date and text cell data in an Excel formula, you need to convert date cells to text to avoid unexpected results.

Excel spreadsheets can contain anything from plain text and numbers to dates and percentages. Excel also enables you to enter a date in a cell without actually setting the cell's type to "Date." ...

Microsoft Excel depends on data that’s stored correctly. If you receive text values that should be real numbers, use one of these methods to get you back to the real work.