math
posted by mima .
the sum of the digits of a two digit prime number is substracted from the number. prove that the difference cannot be a prime number.

adding the digits produces a result that is the remainder when the number is divided by 9.
So, assuming that the prime number p = 9m+n
the sum of the digits is also n
so, pn = 9m, not a prime
Respond to this Question
Similar Questions

Math Prime Numbers
Grade 7 question: I am a twodigit prime number I am one less than a multiple of 10 If you add 30 to me you get another prime number Who am I _________? 
2nd grade
The sum of my ones digit and tens digit is 10. My tens digit is les than my ones digit and both my digits are prime. i am a prime number. what number am i? 
PROBLEM SOLVING IN MATHEMATICS
there are two prime numbers between 100 and 199 such that the ten digits is a prime number, the ones digit is a prime number and the tens and ones digits taken together are a 2 digit prime number. find the sum of these 2 prime number. 
math
I am a 4 digit number greater than 9,000 my omes digit is 3 and my hundreds digit is the smallest prime number greater than 5 the sum of my digits is 20. What number am i? 
math
I am a prime number. I am less than 40. I am 1 more than a multiple of 5. What number am I? 
math
Get the number right. *None of the digits repeat. *It is between 20,000 and 77,777 *The digit in the thousands place is 3 times the digit in the ten thousands place *The ones digit is a prime number *The hundred digit is half the sum … 
Math
What are 2 prime numbers between 100199 such that the tens digit is a prime number, the ones digit is a prime number, and the tens and ones digit taken together are 2 digit prime number. 
Maths
I am a threedigit number. I am divisible by 6. My middle digit is a prime number. The sum of my digit is 9. I am between 400 and 500. My digits are descending order. What number am I? 
math
Neelesh is fond of playing number games. Once when his friends were present he challenged them. He said that he has thought of a fivedigit number and anyone who guesses it correctly can use his cycle for a full day. ‘To help you,’ … 
Math
What is my number? 1.My number is a perfect square 2.The only prime number in it's prime factorization is 2 3.My number is a factor of 32 4. The sum of it's digits is odd.