Using External 10-Key with Keyboard

I have an external 10-key that I plug into my laptop, but to use it I have to have my keyboard on Num Lk and then I can't simultaniously type on the keyboard and use my 10-key  because the right hand letters type the numbers.  Is there anyway to use my external 10-key and type the letters at the same time without having to push Num Lk everytime.  Thats just a pain!  My old HP would let me.

Thanks, Amy