USB Number Pad recommendation for Inspiron 15" 7548

Hello all,

I recently purchased an Inspiron 15" 7548 and notinced it does not come with a number pad.  My question is , is there any number pad in particular that will fit well with this model?

Also, i'm not sure how the number pads work, do they just hang on the side when plugged into the USB?  Do they make them so they become like an attachment so it doesn't just hang around?

thanks in advance