function mysteriousCalculator(a, b) {
var mysteriousVariable = 3;
return {
add: function() {
var result = a + b + mysteriousVariable;
return toFixedTwoPlaces(result);
},
subtract: function() {
var result = a - b - mysteriousVariable;
return toFixedTwoPlaces(result);
}
}
}
function toFixedTwoPlaces(value) {
return value.toFixed(2);
}
var myCalculator = mysteriousCalculator(10.01, 2.01);
myCalculator.add() // 15.02
myCalculator.subtract() // 5.00