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9 = 3*3 and so it is not a prime.

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Q: What is a counterexample of all odd numbers are prime?
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What is a counterexample to the statement all prime numbers are odd?

2 is a prime number.


What number would be a counterexample to the following conjecture Prime numbers are odd?

2 would be a counterexample to the conjecture that prime numbers are odd. 2 is a prime number but it is the only even prime number.


What a counterexample?

a number wich disproves a proposition For example, theprime number 2 is a counterexample to the statement "All prime numbers are odd."


What is a counterexample?

a number wich disproves a proposition For example, theprime number 2 is a counterexample to the statement "All prime numbers are odd."


What is the counterexample of the sum of 2 different prime numbers is even?

2 + 3 = 5 Two plus any odd prime number is odd.


What do 3 5 7 11 and 13 have in common?

They are all odd, and they are all prime numbers


All prime numbers except for 2 are odd?

All of the prime numbers are odd except for two.


What are all prime numbers that are odd numbers?

There is an infinite amount of prime numbers all of which are odd numbers


What's a counterexample to the statement that all odd numbers can be expressed as the sum of two primes?

There is a simple counterexample: the number 1:1 is an odd numberthe first prime is 2 (not 1, see below) which is bigger than 1 so 1 cannot possibly be the sum of two primes.There are plenty of other counterexamples:The sum of two odd numbers is even;All prime numbers except 2 are odd;When adding two prime numbers together, to get an odd result one of them must be even, namely 2;So any odd number that is 2 more than a composite number will not be expressible as the sum of two primes. examples: 11, 17, 23, 27, 29, 35, 37, ...Another counterexample is the number 3:3 is an odd number3 can only be made by 2 + 11 is not a prime (see below)A prime number is a number that has exactly 2 distinct (different) factors.The number 1 has only 1 distinct factor (the number 1) and so is not a prime number; the first prime number is 2.


Is a Conjecture is false all prime numbers are odd?

All prime numbers are not odd. 2 is a prime, 2 is not odd.


Is a prime number always an odd number?

Except for 2 all other prime numbers are odd. Otherwise, they would be divisible by 2 (and thus not a prime number). This does NOT mean that all odd numbers are prime, but that all prime numbers (aside from 2) are odd.


Are there more even prime numbers or odd prime numbers?

All prime numbers are odd, exept of the first prime number 2.