Because everything that ends in an even number is divisible by 2 and everything ending in 5 is divisible by 5. (except 5 itself)
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After 5, all prime numbers end with 1, 3, 7 or 9.
Other than 2, no prime numbers are even. So prime numbers can't end in even numbers. After 5, no prime number can end in 5. After 5, all prime numbers end in 1, 3, 7 or 9.
no
Lots of prime numbers have zeros in them. 101, 103, 107 and 109 are all prime numbers. Prime numbers can't end in zero. Numbers that end in zero are multiples of ten and have too many factors to be prime numbers.
All numbers larger than 5 which end in 5 are divisible by 5 and so are not prime. All numbers larger than 2 which end in 2 are divisible by 2 and so are not prime.