Research has shown that 90% of keyboard users seldom, if ever, use the numeric pad so this section has been removed on compact keyboards. This means the mouse can be placed closer to the keyboard.
Working with a compact keyboard results in greater comfort because it reduces the reaching distance to the mouse (Cook, C., et al., 1998) putting less strain on the shoulder and forearm.
Dark letters on a light background make them easier to read (ISO 9241) and contribute to increased productivity (Snyder, 1990).