Where is my Numbers "app"??

Today, for almost the first time ever, I decided to use the "launch pad", and was rearranging the icons, when a terrible tragedy occurred...

There were TWO Numbers icons, which started wiggling at me, so I DELETED one!

Now, the Dock shows a question mark over the icon

And, when I try to open an existing file, it opens as a Pages or PDF file!

Even worse, I can't figure out how to restore the "app" with Time Machine, OR, how to download a replacement Numbers.

Please help! This is a disaster for me!

Thanks!