what this symbole % dowing

Answer 1

% stands for modulus
It is remainder after division

Like you had 5 guys and 13 apples. 3 apples left xD

Answer 2

It gives you the remainder (if any) after performing the division.
example :
5%2=1;
4%2=0;

Answer 3

@Michael Ermishin;

I've had five guys but that's a different story..