SOURCE

var number2 = 20;
var sum = number1 + number2;
var string1 = "Hi";
var string2 = "Heather";
var string1Number1 = string1 + number1;
var number2String2 = number2 + string2;
var stringNumber1 = number1 + "";
var stringNumber1Number2 = stringNumber1 + number2;

document.write(sum + "<br/>");
document.write(string1Numberl + "<br/>");
document.write(number2String2 + "<br/>");
document.write(stringNumber1Number2 + "<br/>");
document.write(string1 + string2 + "<br/>");
document.write(string1 + string2 + "<br/>");

document.write("---------------------------<br/>");
//
var a=1;
var b=2;

a += b;
document.write(a + "<br/>");
document.write(b + "<br/>");
a -= b;
document.write(a + "<br/>");
a *= b;
document.write(a + "<br/>");
a /= b;
document.write(a + "<br/>");

document.write("---------------------------<br/>");
//

document.write("---------------------------<br/>");
//

document.write("---------------------------<br/>");
//