which of these numbers are prime numbers
89 93
63 75
73 65
74 96
79
99
2007-01-30 08:49:28 · 9 answers · asked by MARKOS KRUGER 5 in Education & Reference ➔ Homework Help
The following site
http://en.wikipedia.org/wiki/Prime_numbers
provides a list. But I'm cheating and the first 30 prime numbers
2, 3, 5, 7, 11, 13, 17, 19, 23, 29, 31, 37, 41, 43, 47, 53, 59, 61, 67, 71, 73, 79, 83, 89, 97, 101, 103, 107, 109, and 113
There is a link at the above link to a more extensive list.
However, it would behoove (benefit) you to understand prime numbers by definition, and, therefore, by determining it's divisibility by other prime numbers.
For instance,
2 is the only even prime number, because every other even number is divisible by 2 as well as 1 and itself.
After prime number 5, no number ending in 0 or 5 is a prime number because each of them has 5 as a factor.
Good luck!!
Lee
2007-01-30 10:58:28 · answer #1 · answered by DLee1210 3 · 0⤊ 0⤋
The first 30 prime numbers are 2, 3, 5, 7, 11, 13, 17, 19, 23, 29, 31, 37, 41, 43, 47, 53, 59, 61, 67, 71, 73, 79, 83, 89, 97, 101, 103, 107, 109, and 113
2007-01-30 16:58:41 · answer #2 · answered by Anonymous · 1⤊ 0⤋
You can quickly eliminate
93, 63, 96 and 99 (divisible by 3)
75, 65 (end in 5 so divisible by 5)
74 (divisible by 2)
So you have to check only for 73, 89, 79. All are prime.
2007-01-30 17:01:53 · answer #3 · answered by Robert W 4 · 0⤊ 0⤋
Here's another hint. If the two numbers add up to a number that can be divided by 3, then its out.
for example: 63 6 + 3 = 9 since 9 can be divided by 3 then, no ... 63 is not prime.
same with 75. 75 can be divided by 5 for one. but it can also add up to 12 (7 + 5 = 12). 12 can be divided by 3, so NO ... 75 is not a prime number.
My guess without a calculator would be: 89, 73, 79
2007-01-30 17:06:38 · answer #4 · answered by Kings Child 3 · 0⤊ 0⤋
A prime number is only divisible by 1 and itself
All even numbers will be divisible by 2 so they will not be prime. So you can forget about 74
then 65 is divisible by 5,,,so forget that one
99 is divisible by 11 so forget that one
I saw the answer below and 93 is not prime it is divisible by 3
2007-01-30 16:54:30 · answer #5 · answered by ? 7 · 0⤊ 0⤋
89 93 73 79
2007-01-30 16:57:21 · answer #6 · answered by t_rav 3 · 0⤊ 1⤋
in addition to Lisa's answer if you add the two digits and that number is divisable by 3, then the whole number is...so that is not a prime number either
2007-01-30 17:02:16 · answer #7 · answered by Anonymous · 0⤊ 0⤋
89,93,63,75,73,65,79 and 99 there is only 2 of them that are not prime because they can be divide by more than 1 and itself.
2007-01-30 16:59:16 · answer #8 · answered by ruth4526 7 · 0⤊ 1⤋
whichever #'s are divisible buy one and itself
2007-01-30 16:57:56 · answer #9 · answered by ME 2 · 0⤊ 0⤋