Question

18. Prime numbers are closed under subtraction.
True or false

Answer 1

the answer is false, phone numbers are not closed under subtraction

Answer 2

Answer: False

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Step-by-step explanation:

We simply need one counterexample to disprove the original claim.

The values 5 and 11 are prime, but 11-5 = 6 is not prime.

We see that taking two primes, and subtracting them, leads to some value outside the set of primes. Therefore, the set of primes is not closed under subtraction.