21, 28, 35, 42, 49, 56
The only numbers between 30 and 50 that could be prime are 31, 33, 35, 37, 39, 41, 43, 45, 47, 49 because all other numbers are even. 35 and 45 cannot be prime because they are divisible by 5. 33 is divisible by 3, so it is not prime, and 49 is divisible by 7, so it is not prime. That leaves numbers 31, 37, 41, 43, 47, so there are five prime numbers between 30 and 50.
There are 10 numbers between 10 and 80 that are divisible by 7 with no remainder: 14, 21, 28, 35, 42, 49, 56, 63, 70, and 77.
All multiples of 49 are divisible by it. Ex: 49, 98, 147 etc
7, 14, 21, 28, 35, 42, 49, 56
21, 28, 35, 42, 49, 56
Besides 49 & 98? The numbers divisible by 49 are infinite.
There are 49 numbers between 1 and 100 that are divisible by two.
The only numbers between 30 and 50 that could be prime are 31, 33, 35, 37, 39, 41, 43, 45, 47, 49 because all other numbers are even. 35 and 45 cannot be prime because they are divisible by 5. 33 is divisible by 3, so it is not prime, and 49 is divisible by 7, so it is not prime. That leaves numbers 31, 37, 41, 43, 47, so there are five prime numbers between 30 and 50.
There are 10 numbers between 10 and 80 that are divisible by 7 with no remainder: 14, 21, 28, 35, 42, 49, 56, 63, 70, and 77.
All multiples of 49 are divisible by it. Ex: 49, 98, 147 etc
7, 14, 21, 28, 35, 42, 49, 56, 63, 70, 77, 84, 91, 98
A number is divisible by 7 if it is a multiple of 7, so to figure it out, start listing multiples of 7. 7, 14, 21, 28, 35, 42, 49, 56, 63, 70, 77, 84, 91, ... On this list there are 11 numbers that are between 11 and 90. The answer is 11 numbers between 11 and 90 are divisible by 7.
7, 14, 21, 28, 35, 42, 49, 56
There are four such numbers: 35, 42, 49 and 56.
Any of its multiples
1, 5, 7, 35, 49, 245