Every camera has a status display in the LCD. One of those numbers is the remaining number of shots you can take. If your camera does not show it, read the manual or search the menu to enable it.
Format the memory card to prepare it properly for the next shoot. The number of shots that appears is the total number of pictures that card can save using your camera.
If you know how may megapixels your camera has then check here too.
Now you know!