Why do Westerners write the number 7 as a backwards F?
916857
not everyone does this.  anyway, the answer is because they were taught to do so.  I think it was to be sure the number didn't get confused with another.
78661
Palindromes.  The same fowards as is backwards.  Like "Madam, I am Adam."
1026499
Move the first letter to the back, and it spells it backward.\nExample:\n\nbanana..\nbecomes Ananab\nWhich is banana backwards.
1151383
Oh, dear.  Someone's been insulted.  It's F***, of course.\n|= is F\n&#92;_/ is U\n( is C\nand |< is K\n\nThis could be leet (excuse be, 1337), where a techy person uses symbols and numbers that look like a normal English word.\nOr else someone's just trying to be funny.
389901
what ? \n\nyou mean why is it 2U(doube u) instead of 2V(double V) ?\n\nWell, because DoubleU goes back to the time when they wrote everything in cursive. And when you write a W in cursive, it doesn't look anything like 2 V's
963168
Well...why don't you find out and tell me next time we come across each other?\n\nWell...anyway, none of the others are pronunced like that too.\n\n22 - twoteetwo? lol\n\n33 - threeteethree? even more hilarious\n\nonly 44 is like that - and 66, 77, 88, 99\n\n55 - fivetyfive? nah\n\nThe English Language has no permanent rule, since it takes the roots of too many other languages. Nothing makes sense.
347804
the number 7 on a phone
342459
Since there are seven ones, it will count up to 7 and then back down - 1234567654321.\n\n 1111111\nx1111111\n-------------\n0000001111111\n0000011111110\n0000111111100\n0001111111000\n0011111110000\n0111111100000\n1111111000000\n-------------\n1234567654321
112490
Because the numbers after the decimal (to the right of) represent less than one. One times a number is that number. Less than one times a number is only a fraction of that number.\n\nMake sense?
146915
It is called a palindrome and it applies for words or lines that read the same forward or backwards.\nThe word is of greek origin from "palin + dromo" (back + way)
643149
Why do you people use letters like that?
933918
Well, the best help that I've got is that, when the numbers are reversed, they are the squares of 4, 14, 19, 28, and 32 respectively.  This is at least an ascending sequence, and too much of a coincidence to be ignored, but I'm hard pressed to see any the pattern in that either.\n\nUPDATE: After reading the previous answer, I believe the answer to be 9631.  The numbers in the pattern are all prime, and all squares with the digits reversed.  In fact, of the numbers 1-32, those five are the only ones that, when you reverse the digits of their squares, make prime numbers.  So, continuing that sequence, the next number whose reversed sqare is a prime is 37. 37 squared is 1369, and so the reverse is 9631.
454426
i have a great logical reasoning for that.... here goes:\n1. there are two 2s, so you overlap them, making just one two. \n2. take the plus sign out for a second.\n2 1/2. the plus sign consists of 2 sticks, one horizantal and one vertical. \n3. the vertical came become a one and place it on the left of the 2. ( it makes 12)\n4. the other horizantal line can be used as a minus sign. \n5. Now, in the equal sign, it consists of two lines, both horizantal. \n5 1/2. if you leave one, and make the other diagonal, and attach in together, it makes a seven. \n6. so.. so far, it's is like this: 12-7=?\n7. ultimately, the answers five\nso there you have it, it sounds a little weird and strange, but it's really impossible to have a logical reasoning for 2+2=5... hehe
1142715
The Arabs invented the system of writing numbers that use a zero and positions.  All earlier number systems used different characters to represent "50" than to represent "5" for instance.  The use of the zero makes it easy to write larger numbers than could easily be written in other number systems.  Try to write any number above a million in Roman numerals if you don't believe me...\n\nYes, Arabic *does* use other forms for the numbers (although 1 and 9 are similar to the digits you are familiar with--see sources section below), but the point is that they have the same ten basic digits and use position within the number to express the same ideas.
527962
The $ sign is always before the number.\nOnly when pounds or rupees or pesos or yuan or yen... are spelt out, then they are behind the number.
287161
Yes, I just discovered that myself today.  I had to type the word out.  Maybe it's so people can't type 6nine?  That's the only logical thing I could come up with.
622768
A score is exactly twenty.  \n\nSo four scores and seven years ago is actually 87 years ago.\n\nKind of fun isn't it...\n\nSince we are talking about names of numbers -- did you know that eleven comes from the Old English for "one left over." -- So, now that you know that, I bet you have some idea where twelve comes from -- what do you think it might be?\n\nJust in case, you are in doubt it is also Old English in its origin and yes you guessed it -- it means "two left over."\n\nAh, the joys of English Literature being applied to Mathematics.\n\nBest wishes,  \n\nMrMerchant