A numeric keypad, number pad, numpad, or ten key,[1][2][3] is the palm-sized, usually-17-key section of a standard computer keyboard, usually on the far right. It provides calculator-style efficiency for entering numbers. The idea of a 10-key number pad cluster was originally introduced by Tadao Kashio, the developer of Casio electronic calculators.[citation needed]
The numpad's keys are digits 0 to 9, + (addition), - (subtraction), * (multiplication) and / (division) symbols, . (decimal point), Num Lock, and ↵ Enter keys.[4] 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. Some specialist numpads may also include an additional 000 key).
Sometimes it is necessary to distinguish between a key on the numpad and an equivalent key elsewhere on the keyboard. For example, depending on the software in use,[a] pressing the numpad's 0 key may produce different results than pressing the alphanumeric 0 key.[b] In such cases, the numpad-specific key may be indicated as e.g. Numpad 0, NumPad0 [c], Num 0, or likewise to remove ambiguity.
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.
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.
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.
A numpad is also useful on Windows PCs for typing alt codes for special symbols, for example the degree symbol, °, with Alt+0176. Technically, the previous example's method using a leading 0 (ANSI alt code) only works when used with the numpad's own keys, so it could be written less ambiguously (if necessary) using one of the notations mentioned above, e.g. Alt+Numpad 0Numpad 1Numpad 7Numpad 6. When entering a hex Unicode value, only the leading '+' needs to be the Numpad + key, so this notation can be used sparingly, e.g. Alt+Numpad +11b yields ě.[d]
To maintain their compact size, Mac laptops and most PC notebooks do not include a numeric keypad. To compensate for it, most PCs include Num Lock integrated into a function key (typically F6 or F8) and then press keys like 7 to produce a numpad 7, although some PC notebooks do not include such shortcuts.
