SOLUTION: What is the greatest prime you must consider to test whether 503 is prime? I tried the smaller numbers, 2, 3, 5, 7 and then looked at a prime chart and it said it was prime, but h

Algebra ->  Divisibility and Prime Numbers -> SOLUTION: What is the greatest prime you must consider to test whether 503 is prime? I tried the smaller numbers, 2, 3, 5, 7 and then looked at a prime chart and it said it was prime, but h      Log On


   



Question 225297: What is the greatest prime you must consider to test whether 503 is prime?
I tried the smaller numbers, 2, 3, 5, 7 and then looked at a prime chart and it said it was prime, but how do I test it and choose the greatest prime?

Answer by ankor@dixie-net.com(22740) About Me  (Show Source):
You can put this solution on YOUR website!
What is the greatest prime you must consider to test whether 503 is prime?
:
Find the square root of 503 = 22.47....
You know the greatest prime (if it has one) has to be less than 22
that would be 19, you can check it with all primes less than 19