Assuming dates start in B2 then use the following formula and copy down as needed

```
=Date(left(B2,4),Right(B2,2),1)
```

Then apply custom formatting to the cells and set the date format to be mm/yyyy. This method will basically convert your numbered date to a date recognizable by excel and which excel date functions will work with.

### Altenative

You could opt to simply treat your date as text which may make it harder to work with down the line if you want to go that route you could use the following formula:

```
=RIGHT(B2,2)&"/"&LEFT(B2,4)
```

### UPDATE: Blank Cells

To deal with blank cells, check to see if the cell is blank first. If the cell is blank return a blank. If its not blank then perform the operation:

```
=IF(B2="","",Date(left(B2,4),Right(B2,2),1))
```