If you have a new iMac you probably don't have a numeric pad on your keyboard. NumPad Connector for Mac is the application that solves this problem, connecting your iMac to your iPhone, iPad or iPod Touch and transforming them into a wireless numeric keypad.
The application costs $2.99, while the connector that you'll need for the iMac is free. NumPad Connector for Mac is a small application that you install on your device and then connect to your MacBook or to the Bluetooth wireless keyboard of your iMac. In order to do so, you have to set the "sharing screen" preference and the VNC password on the iMac. Once that's done you'll have to choose your iMac on the device you are using and enter the VNC password in order for your device to turn into the numeric pad you need. When testing this software with an iPod Touch we sometimes noticed a short delay between pressing the numbers and their appearance on the iMac. It's nice that you can choose between delimiters but some more customization of the numeric pad would be nice for users with different needs.
Turning your external device into a numeric pad can be really useful when you don't have one integrated in the keyboard of your iMac or MacBook. NumPad Connector for Mac can be an easy solution for a small price, although it lacks some features and is rather slow.