Eval function

Question

var x = "2*2";
var y = 4;
var z = eval(x + y);
console.log(z);

//output: 48

can any one expline it, why 48 ?

Answer 1

x = 2*2, y = 4
eval( x+y) => 2*2 + 4 => 2*24 ( + does concatenation)
eval( 2*24 ) => 48
So z = 48