I'm not really sure this is an app question as something my be availble already that I'm not aware of.
If I'm on the phone, and driving (Bluetooth headset), very often the party I'm talking to wants to give me a number. If I don't have a paper and pencil then I need to put it in my phone. I can't get to the dial pad so I have to go to a notepad app where the stock android keypad comes up and is impossible to safely put in a phone number. But if I could bring up a big number pad like the dial pad it would be easy.
How do other people do it?