2007-03-29 00:29:51 · 7 answers · asked by curious 1 in Science & Mathematics ➔ Mathematics
I mean how do they find large prime numbers like numbers of 100 digits .
2007-04-01 22:26:48 · update #1
Numbers that have the factors 1 and itself. To find prime numbers between 1 and 100, you find the numbers in the 2 times table, 3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18, 19 times tables to be safe.
by the way, 1 is NOT a prime number, no matter what your textbook says.
2007-03-29 00:35:01 · answer #1 · answered by mr_maths_man 3 · 1⤊ 1⤋
Use the Sieve of Eratosthenes.
Write out the numbers that you would like to check, like maybe from 1 to 100. Circle the smallest number and cross out all the multiples of 2. Then circle the next prime, 3, and cross out all multiples of 3. Cricled numbers are prime numbers and non-primes are sifted out.
2007-04-05 11:34:51 · answer #2 · answered by moongood 2 · 0⤊ 0⤋
Computers are the best at figuring the big ones.
Iterative operations within processors can figure the big ones quite easily. There must be tons of algorithms to look for shortcuts, but at today's PC speeds, a simple handful lines of code will do just fine for any practical purposes.
2007-04-04 00:31:09 · answer #3 · answered by felasbigdaddy 2 · 0⤊ 0⤋
Factoring and charts work too. Just type in "prime number charts"on yahoo search.
2007-04-05 12:33:56 · answer #4 · answered by dwinbaycity 5 · 0⤊ 0⤋
they are numbers that are only divisible by 1....basically keep dividing the number by other numbers if it can only be divided by one then it must be prime
2007-03-29 08:14:19 · answer #5 · answered by Curly Girl 3 · 0⤊ 0⤋
if a number has more than two factors is a composite number
Is a number has only two factors 1 and itself it is prime.
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2007-03-29 10:44:32 · answer #6 · answered by SAMUEL D 7 · 0⤊ 0⤋
Using computer programs that can test each number exhaustively.
2007-04-04 14:19:54 · answer #7 · answered by kathyw 7 · 0⤊ 0⤋