Answer 1

could you please be more specific?
Prime Numbers are numbers which are only divisible by 1 and the number itself. Ex :
2 , 3 , 5 , 7 , 11 , 13 , 17 are prime numbers
while 4 , 6 , 8 , 9 , 10 , 12 , 14 , 15 , 16 aren't.