If you are not using your laptop as mini cinema and you need to compute things and perform mathematical functions to your daily transactions as accountant or engineer then smaller laptops is the next solution.

Apple has already eliminated 17-inch laptop from its lineup. Even the 15-inch MacBook Pro seems to be falling out of favor, as the 13-inch size emerges as the new standard. For the MacBook Air, many reviewers cite the 11-inch model as preferable to the 13-inch.

A similar situation exists with the iPad Air vs iPad mini, with a majority of reviews leaning towards a preference for the mini.

Even techno-savvy “power users” that write reviews, and for whom price is usually not a prime consideration, often say they want the smallest model they can get. Apple’s new Mac Pro is lauded for its small size, compared to the old Mac Pro behemoth even though the size reduction comes at the expense of internal expandability.

Business PCs were initially accounting machines and often sat on the accountant's desk, so of course once this was realized they were designed with the UI accountants were most familiar with, the 10 key numeric keypad (which old school accountants could operate by touch at blinding speed).

When the Mac came out it didn't have the numeric keypad, which basically meant Mac's couldn't be used for accounting and it really limited their market at the time, so later Mac's included the numeric keypad.

But soon computers were used for many things other than accounting, nevertheless the most popular keyboards had the numeric keypad so they could function as accounting machines if needed.

Numpads require some great space on laptops. With the reduction in size of laptops, num pads have also been removed as a result. Here comes the need for separate num pads especially for those who extensively utilize digits.

Separate num pads are very useful when you need to type many numbers. It is much easier to have them all in their own area and it's much faster than using the ones above the letters.

Nowadays many 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 separate numpads are needed 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).

These 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. They may be used on Windows PCs for typing special symbols such as the degree symbol.

The separate numpad is also useful when you want to enter a lot of numbers in a row since its multirow layout vs the numbers above the letters enables you to type with little movement of one hand vs two hands and probably with less typos, as you can feel your exact location within the numpad even if you are not experienced at typing.

Both numpads with and without TAB button are avaliable at the links below: