Why is the keypad of phones different from the numeric keypad of calculators?
444351
It is pretty odd that a calculator and a touch-tone telephone have exactly opposite layouts for their keypads, which have many identical components. The reasons behind the differences are not known for certain, but a few theories exist.\n\nThe first theory deals with the telephone's circuitry and tone-recognition hardware. When the touch-tone telephone was being designed in the late 1950s, the calculator and adding-machine designers had already established a layout that had 7, 8 and 9 across the top row. Data-entry professionals, and others who used calculators fairly regularly, were quite adept at navigating these keypads. They could hit the numbers extremely quickly, which was great for data entry, but not so great for dialing a touch-tone phone. The tone-recognition technology could not operate effectively at the speeds at which these specialists could dial the numbers. The telephone designers figured that if they reversed the layout, the dialing speeds would decrease and the tone-recognition would be able to do its job more reliably. This theory has little proof to substantiate it, but it does make sense.\n\nA second theory refers to a study done by Bell Labs in 1960. This study involved testing several different telephone-keypad layouts to find out which was easiest to master. After testing several layouts, including one that used two rows with five numbers each and another that used a circular positioning, it was determined that the three-by-three matrix that had 1, 2 and 3 across the top was the easiest for people to use.\n\nAnother theory is based on the layout of a rotary telephone. On a rotary dial, 1 is at the top right and zero is on the bottom. When designing the new touch-tone keypad, putting the 1 on the top-right didn't make much sense, because Western writing is read from left to right. But putting 1 on the top-left, and the subsequent numbers to the right, did make sense. Using that formula, the resulting rows fell into place, with zero getting its own row at the bottom.\n\nAll of these theories attempt to explain why telephone and calculator keypads are exact opposites, yet no one theory can be pinpointed as the definitive reason. It is common practice today to use the telephone-keypad layout when designing new products that utilize a keypad, such as Automated Teller Machines.
825061
i think you need a set of numbers to deviate from first, and then you can easily google both of these. then it is just a bunch of calculator work
917226
Many calculators now come with a backspace button.  It looks like an arrow that points to the left (←).  It is not just on Casio's or HP's.  Many TI's also have this feature.  I don't think you would find this on too many cheap calculators though.
32567
Are to talking about the little line that's raised a little (if so there should be one on the 'J' key too)?  If you are, it's so you can feel whether or not your fingers are in the right place.  It reduces the need to look at the keyboad while typing (and I image would be extremely useful for blind people).  Incidently, on old Apple keyboards, there is a circular bump on 'D' and 'K' rather than a horizontal line bump on 'F' and 'J,' but at some point a few years back they changed it to match Microsoft keyboards so it would be easier to swtich back and forth between the two (if you can find an old Apple keyboard, try typing on it - it feels weirder than you might expect).
226135
When the touch-tone telephone was being designed in the late 1950s, the calculator and adding-machine designers had already established a layout that had 7, 8 and 9 across the top row. Data-entry professionals, and others who used calculators fairly regularly, were quite adept at navigating these keypads. They could hit the numbers extremely quickly, which was great for data entry, but not so great for dialing a touch-tone phone. The tone-recognition technology could not operate effectively at the speeds at which these specialists could dial the numbers. The telephone designers figured that if they reversed the layout, the dialing speeds would decrease and the tone-recognition would be able to do its job more reliably. This theory has little proof to substantiate it, but it does make sense :)
179488
Standard computer keyboards have the @ above the 2 and the " above the '.\n\nThat's the way all keyboards are designed. I don't think there's a way to switch them around.\n\nI haven't seen the " above the 2 since the old mechanical typewriters.\n\nThis is the way it is now.  Every keyboard made is this way. I would really recommend getting used to it. It's not going to change.
533811
The numbers on a computer number-pad are designed for easy entry of a whole series of numbers - number-crunching as it were (these are the true confessions of a former accountant!) - having the zero on the bottom is the quickest arrangement for rapid data-entry; the numbers on a phone / ATM (and remote controls) on the other hand are designed as a replacement for the rotary dial which had that same sequence, and also included the letters of the alphabet - which is the basis of the current SMS / text messaging system. You don't need to enter as many numbers on a phone key-pad, and having the numbers and letters both arranged in ascending order helps us to remember the association.
747484
Press Alt+1+5+6 (All numbers on the number pad, with Num Lock turned on). The result is this: £
1133787
Wow, I'm getting old, I can actually remember this one, as I was a kid back in the 1970s when touch-tone keypads came out for telephones in widespread use.  (yes, they were invented earlier, but note the words "widespread use" please)  :p\n\nThe way the numbers are arranged on electronic calculators was copied from the way they were on older, electric and mechanical cash registers and calculating machines that had been in widespread use in stores and business for several decades before touch-tone phones and their keypads came along.  It was a fairly logical and effective way to arrange the numbers, and a *lot* of folks in accounting and cashiering and old-school keyboarding businesses like bank telling were very VERY quick with this layout, able to crunch numbers as quickly with a mechanical system as some do with the electronic ones today.\n\nWhich didn't sit well with the phone companies in the 1970s because this touch-tone technology was new and at the time it actually had have a) a bit of a time delay between individual tones, and b) each tone had to be selected for close to a full second, in order for the older phone-line switching systems to keep up and get numbers dialed accurately, especially in parts of the country that converted to touch-tone later than others, or parts of the world that had held on to not just pulse dialing, but literally *mechanical* rotary dialing well into the mid-1990s (not the U.S. so much as places around the world you could *call* from the U.S.).\n\nIn other words, in the beginning the touch-tone phone dialing system coudn't keep up with some of the speedier keypad operators that had worked for a living running keypads all day on cash registers and mechanical calculators.  So the phone company (and back then it was all Bell) had to come up with a way to slow folks down across the board, in much the same way and for much the same reasons that the QWERTY key layout for mechanical typerwriters had been designed the way it was over half a century earlier....\n\nThey inverted the keys so that folks wouldn't freeze up the phone system and annoy customers to the point of giving up on touch-tone and refusing to use it.   And like QWERTY on keyboards, we are still stuck with it to this day.
605693
Consider holding down the Alt key whilst typing 253 on the numeric keypad - it would make this easier to read:\n4r²-25s²/2r²+3rs-20s\nor should it be:\n4r²-25s²/(2r²)+3rs-20s\nor:\n4r²-25s²\n--------\n2r²+3rs-20s
914094
Yes, that's because American keyboards are laid out differently than UK keyboards, as you found out.
130987
These are usually trick questions.  For example, when you type a 2 on a cheap calculator and turn it upside down, it looks like a 5.  So 2-55 :: 6 - 99 (because 6 upside down is 9).  \n\nThe second one, 23-3983::32-? (3,839 , 3,994 , 4,874 , 9,599) ,unless you typed the answers wrong, is 9,599 because the first number is the sum of the digits of the second one.
146088
If you're talking about this: ♥ then all you have to do is press Alt and 3 on the number keypad at the same time. Some fonts don't support that character, though. So if you end up getting a ? or some other symbol, try changing the font.
1170365
If I recall, it's something along the lines of ALT + 3. It's a single number, lower digits. I'm on a laptop, so I can't test it.
681399
Cell phones with super small keypads are not user friendly.
877336
If you have the TI-34 calculator, you will need to use the 2nd function key and then push the >D key (2nd column, 3rd row) to access the A b/c key.\nI don't own any of these calculators, but I would imagine that it is going to be a second function key, which means you will need to look for the small text written above each key.  Which model of a calculator do you have?
195054
The QWERTY keyboard was designed ergonomicallyso that the most often used keys would be appropriately placed for easy reach.  The other (not so) big layout is where the keys are arranged in alphabetical order.  I don't recomend this as a solution.  Here is another to investigate as well: Dvorak