there are 13 primes not 5.
There are only 2 primes in 80: 2 and 5.
There are 169 primes that are smaller than 1000.
There 25 primes less than 100: 2,3,5,7,11,13,17,19,23,29,31,37,41,43,47,53,59,61,67,71,73,79,83,89,97.
There are 5,761,455 primes less than 100,000,000. The largest of which is 99,999,989.
it is infinite
All pairs of two primes are coprime. There are fifteen primes under 50. So that means there are 105 unique pairs of "coprime primes", or more generally, pairs of primes, under 50.
There are infinitely many twin primes. One example is 5 and 7.
One pair of twin primes between 135 and 145
101
25 of them.
25 of them.