There are only 9 numbers between 80 and 90 - so lets look at them all
Remember we only need to find 1 number that will divide the number except for 1 and itself for it to be NON-PRIME.
81 - 3 will of course divide this number - so not prime.
82 - 2 will of course divide this number - so not prime.
83 - PRIME!!!
84 - 3 will of course divide this number - so not prime.
85 - 5 will of course divide this number - so not prime.
86 - 2 will of course divide this number - so not prime.
87 - 3 will of course divide this number - so not prime.
88 - 2 will of course divide this number - so not prime.
89 - PRIME!!!
So, the only numbers between 80 and 90 that are primes are 83 and 89!
The average of the prime numbers between 80 and 90 is 83.
There are 2 prime numbers between 80 and 90: 83 89
83,87,89
The prime numbers between 80 and 90 are 83 and 89.
Two.
83 and 89.
172
170
All of them except for 83 and 89 which are prime numbers
The product of 83 and 89 is 7387
The only prime numbers between 81 and 90 is... 83
The sum of prime numbers between 90 and 100 is 97, the only prime number between 90 and 100.