Question

find the greatest prime number which is less than 45​

Answer 1

Answer:

That would be 43.

Explanation:

In case you need clarification, a prime number is simply a number greater than one, where dividing by any positive integer other than itself or one results in a decimal answer. For example we know that 4 can be divided by 2 to result in 2, so since we divided not by 1 or 4, and we got a positive integer in return, we know 4 is obviously not prime. Another example, let’s use 17. Dividing by a number greater than 17 would result in a number less than one, which is obviously not the result we desire. Let’s test by dividing it by 16, 15, 14, 13, 12…, and we see nothing provides us with a nice positive integer other than 1 or 17. Thus, 17 is prime.

We don’t categorize 1 as a prime number because then we would essentially contradict ourselves, and although there are other valid explanations, this is a fairly simple one regarding the question “Is 1 prime?”

If you wanted to brute force your solution the most efficient way would be to determine if 44 was prime. Since we easily see that it can be divided by 2, 4, 11, and 22, we know that isn’t a prime. We move on to 43, and don’t see any common divisibility traits, so we try other divisors like 7, 13, 17, etc., to no avail. 43, therefore, is your desired answer.

For future note, primes within the range of 1 and 45 include:

2, 3, 5, 7, 11, 13, 17, 19, 23, 29, 31, 37, 41, 43.

Hope this helps!

Answer 2

Explanation:

$\huge\mathfrak{\underline{\underline{Answer}}}$

Greatest prime number which is less than 45 is 43

A prime number is a number which has only one factor 1 and itself.

Example:

2 ,3 ,5 , 7 ,11, 13, 17 ,19, 23, 29 ,31 ,37 ,41 ,43,.......