I want to transfer songs off my IPAD and leave them in my Library on my computer in case I ever want to put them back on my IPAD. How do I do that?

The same way you put the music onto the iPad via iTunes, select and de-select followed by a sync.

Sync with iTunes and the songs should transfer into your iTunes library. Have you synced with your computer in the past? That's reall all that you should need to do, but you can also initiate the transfer of purchases into iTunes.

When you connect the iPad to your computer and launch iTunes, right click on the iPad name under Devices on the left sidebar and select - Transfer Purchases.

You can also download the songs again for free as long as you use the same Apple ID that you bought them with and as long as the songs are still available in iTunes... And as long as you live in a country where free music downloads are available. You can read about what content is available again for free here.

http://support.apple.com/kb/ht5085

after you transfer the music into your iTunes library, you can delete it from the device by swiping across songs in the Songs tab of the Music app to bring up the red delete button or tap and hold down on an album icon in order to bring up the X to delete.

Or you can deselect the songs, albums, playlists, etc in iTunes and sync again in order to remove them from the iPad.

Note - when you delete songs from the iPad that does not delete them from your iTunes library on the computer.

Glad to help.