What is the difference between Pre increment and post increment?

Question

can anyone explain by using it in arithmetic expressions?

Answer 1

x = 10;
return x++/2;
//5

x = 9;
return ++x/2;
//5

Answer 2

x = 10;
return x++;
//10
return x;
//11

x = 10;
return ++x/
//11

Answer 3

x++/2 ;
//what will be the results and effects?

++x/2;