Explain me pre n post increment n decrement in detail

Question

please help
I'm new to JavaScript

Answer 1

var num=0;
document.write(num++); // first prints 0 because firstly num has 0, so it prints..later it does operation increment..

document.write(num);//after increment..
document.write(++num);//increments by 1 and then it prints

Answer 2

I got it
Bt need a little nore

Answer 3

can u please help me again