Asked by GJ

What is the sum of the unique prime factors of 9991?
Answered by Amanda
Well the answer would be 220. Are you asking for Math Counts??
Answered by Amanda
Wait whoops I meant 200
Answered by Olivia
Yeah it is 200
Answered by Alwin
Wow, a lot of Mathcounts people here
Answered by rather not
200 I am in mathcounts and had it for homework
Answered by Hemi
Hi can some pls show the method of solving it.
"What is the sum of the unique prime factors of 9991?"
Answered by Maddy zhang
dang mathcounts members aren't even trying anymore lol
Answered by NoobMaster69
I'm also in mathcounts and was searching for the answer in the internet and I found it.
Answered by Thiago
So, any non-prime number is formed by a product of prime numbers, then if 9991 isn´t prime, we can find its factors. Given that 9991 is a four-digit number, we can start dividing it by primes that are at least bigger than 90 (given that 90^2= 8100), so the first prime above 90 is 97. So 9991/97=103 and 103 is a prime and the 2nd prime factor. Therefore, the sum of the primes is 103 + 97 = 200.

list of prime numbers between 1 and 100: 2, 3, 5, 7, 11, 13, 17, 19, 23, 29, 31, 37, 41, 43, 47, 53, 59, 61, 67, 71, 73, 79, 83, 89, and 97.
Answered by Anonymous
Thx this really helped and no I’m not in math counts I just got it for homework.
Answered by PGS × Zoyyo
200 i had it for classwork
Answered by not giving my first name
Also in math counts. Man, so many math count students.
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