25
'from 100' ??? If you mean 'less than 100' then there are 25 primes. If you mean 'more than 100' then the answer is infinite, just like numbers are infinite.
the largest prime number under 100 is 97
There are 168 prime numbers under 1,000 . There are also 25 primes under 100, 62 primes under 300, and 95 primes under 500
91,97 are the two large prime numbers below 100.
The highest prime number under 100 is 97.
1060
It's not a case of working them out, you just have to know them. Here are the following prime numbers under 100:
There are 25 prime numbers less than 100
There are 25 prime numbers between 1 and 100.
100
The answer depends on how many prime numbers are whose!