the + operator some times it does nt add the numbers instead it concat those 2 numbers?

Question

for example
var a =2;
var b=5;
var result= a+b;
document.write(result);

o/p : 25

Answer 1

It concatenates strings and adds numbers.
var a="2";
var b="3";
document.write(a+b);
Returns 23.

var a=2;
var b=3;
document.write(a+b);
Returns 5.

Answer 2

JavaScript concatenates string and add numbers.

Answer 3

When you want to add, avoid single or double quotes when dealing with numbers else JavaScript will take them as strings. when that happens, you get concatenation instead of addition.