var undefinedVar= "";
undefined
console.log (undefinedVar);
VM2781:1 
undefined
var nullVal= null;
undefined
console.log (nullVal);
VM2940:1 null
undefined
console.log (undefinedVar/nullVal);
VM3144:1 NaN
undefined
var myAge = 25;
undefined
myAge = myAge * 4;
100
console.log( typeof (myAge) );
VM3408:1 number
undefined
console.log (myAge - 20)
VM3532:1 80
undefined
console.log( typeof (pets))
VM3673:1 undefined
undefined
var dogs = "pets";
undefined
console.log (typeof(pets));
VM3878:1 undefined
undefined
console.log (typeof(nulVal));
VM4010:1 undefined
undefined
console.log (typeof(nullVal));

VM4016:1 object
undefined