Spying on a javascript function

//how to spy on a normal java script function ???
//note when I try to access it with $scope.arithmetic I am getting errors
function arithmetic() {
addFn(value1, value2);
subFn(value1, value2);
multFn(value 1, value 2);
DivFn(value 1, value 2);
}

//spec.js
.....
.....
spyOn(scope, 'arithmetic');
scope.arithmetic();
expect(scope.arithmetic).toHaveBeenCalled();
//but I also want to check whether these functions add, mult .... have been called. so how do I do this?