Use the prime number of two digits of 1,5,6 (), sum number (), multiple of 2 (), multiple of 3 (), multiple of 5 (), which is not only a multiple of 3 but also a multiple of 5

Use the prime number of two digits of 1,5,6 (), sum number (), multiple of 2 (), multiple of 3 (), multiple of 5 (), which is not only a multiple of 3 but also a multiple of 5

Two digit prime (61),
Total number (15,16,51,56,65),
2 (16,56),
3 (15,51),
5 (15,65),
It's a multiple of 3 and a multiple of 5: 15

Proof: any prime number greater than 3 plus or minus one must be a multiple of 6
RT.

One of every three consecutive numbers must be a multiple of three
Let this prime number be called a. a must be an odd number (because it is a prime number) which is not a multiple of 3
Then A-1, a + 1, one of them must be a multiple of 3
Obviously, both A-1 and a + 1 are even numbers, that is, multiples of 2
So there must be a number that is a multiple of 2 and a multiple of 3
It's a multiple of six