No.
Yes.
Yes.
Between 65 and 100, there are 34 other whole numbers plus an infinite number of decimals and mixed numbers.
An infinite lot of numbers: 51.23689752, for example.
All numbers have an infinite amount of multiples.
All of those numbers have infinite multiples.
That infinite list would include all of the natural numbers, minus only the first 100. It begins at 101 and continues infinitely.
'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.
1099
There are infinitely many primes. There are 24 prime numbers between 1 and 100
If the question is about all NUMBERS, then the answer is infinite. If the question is about all integers, the answer is 5050.
The sum of the squares of the first 100 natural numbers [1..100] is 338350, while the sum of the first 100 natural numbers squared is 25502500.