I created a small dataset in Excel about dates. The column of months had to be combined to the column of years, with a slash in between. This is how I created and then combined the contents of cells. You will see several shortcuts and tricks for using Excel.
The formula to combine the cells is =B2&"/"&A2. This creates a single cell comprising the numeric month in cell B2, then a slash, and the actual value in cell A2, which is the year.