<P> Laptop keyboards often do not have a numpad, but may provide numpad input by holding a modifier key (typically labelled Fn) and operating keys on the standard keyboard . Particularly large laptops (typically those with a 15.6 inch screen or larger) may have space for a real numpad, and many companies sell separate numpads which connect to the host laptop by a USB connection (many of these also add an additional spacebar off to the side of the zero where the thumb is located, as well as an additional 00 key typical of modern adding machines and cash registers). </P> <P> Numeric keypads usually operate in two modes . When Num Lock is off, keys 8, 6, 2, and 4 act like arrow / navigation keys up, right, down, and left; and 7, 9, 3, and 1 act like Home, PgUp, PgDn, and End, respectively . When Num Lock is on, digit keys produce the corresponding digit . On Apple Macintosh computers, which lack a Num Lock key, the numeric keypad always produces only numbers; the Num Lock key is replaced by the Clear key . </P> <P> The arrangement of digits on numeric keypads with the 7 - 8 - 9 keys two rows above the 1 - 2 - 3 keys is derived from calculators and cash registers . It is notably different from the layout of telephone Touch - Tone keypads which have the 1 - 2 - 3 keys on top and 7 - 8 - 9 keys on the third row . </P> <P> Numeric keypads are useful for entering long sequences of numbers quickly, for example in spreadsheets, financial / accounting programs, and calculators . Input in this style is similar to a calculator or adding machine . </P>

Keys used to press in order to function the numeric keys