var a=10;
var b=5;
var c=++a-b;
console.log(c);
c=6
var a=10;
var b=5;
var c=a++-b;
console.log(c);
c=5
var a=10;
var b=5;
var c=a++;
var d=a++-b;
console.log(a);
console.log(b);
console.log(c)
console.log(d);

image.png
var a=10;
var b=5;
var c=++a-b;
console.log(c);
c=6
var a=10;
var b=5;
var c=a++-b;
console.log(c);
c=5
var a=10;
var b=5;
var c=a++;
var d=a++-b;
console.log(a);
console.log(b);
console.log(c)
console.log(d);