Question 105738
A prime number is a number that can only be divided by itself or 1 to get an integer as
an answer.  For example is 3 a prime number? Yes it is because it can only be divided
by 3 and 1 to get an integer as an answer. How about 6 ... is it a prime number? No it is
not because it can be divided by 6, by 1, by 3, and by 2 and each of those divisions
results in an integer as an answer.
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You are to find all the prime numbers between 55 and 75. Note that both 55 and 75 are not
prime numbers because both can be divided by 5.
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56 is not prime ... it can be divided by 2. From this you can deduce that any even number (except 2) 
is not a prime because it can be divided by 2.  Therefore, only odd numbers can be a prime
and every odd number is not a prime. And any number that ends in 5 is not prime because it
can be divided by 5 and produce a quotient that is an integer. (2 is an exception 
to this rule. It is prime because even though it is even, it can only be divided by itself
and 1 ... so it fits the definition of prime.)
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The prime numbers between 55 and 75 are: 59, 61, 67, 71, and 73. Any other numbers in
this range are divisible by something other than themselves and 1. Any of the other numbers
in this range have at least a 2 or a 3 or a 5 as a divisor.
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Hope this clarifies the term "prime" for you and helps you to see your way through the
problem.
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