What is the product of all the numbers that appear in the dial pad of our mobile phones?

Since one of the numbers on the dial of a telephone is zero, so the product of all the numbers on it is 0.

The layout of the digit keys is different from that commonly appearing on calculators and numeric keypads. This layout was chosen after extensive human factors testing at Bell Labs. At the time (late 1950s), mechanical calculators were not widespread, and few people had experience with them. Indeed, calculators were only just starting to settle on a common layout; a 1955 paper states “Of the several calculating devices we have been able to look at… Two other calculators have keysets resembling [the layout that would become the most common layout]…. Most other calculators have their keys reading upward in vertical rows of ten,” while a 1960 paper, just five years later, refers to today’s common calculator layout as “the arrangement frequently found in ten-key adding machines”. In any case, Bell Labs testing found that the telephone layout with 1, 2, and 3 in the top row, was slightly faster than the calculator layout with them in the bottom row.

The key labeled ? was officially named the “star” key. The original design used a symbol with six points, but an asterisk (*) with five points commonly appears in printing.[citation needed] The key labeled # is officially called the “number sign” key, but other names such as “pound”, “hash”, “hex”, “octothorpe”, “gate”, “lattice”, and “square”, are common, depending on national or personal preference. The Greek symbols alpha and omega had been planned originally.

These can be used for special functions. For example, in the UK, users can order a 7:30 am alarm call from a BT telephone exchange by dialing: *55*0730#.

 

Picture Credit : Google