I just took the simplest demo from http://docs.angularjs.org/api/ng.filter:orderBy and just change the value of age to have different number of digit. It stop working as it
you have to convert age to type Number to make to orderBy to work as it should.
orderBy
Add to your controller to sort String age as float:
angular.forEach($scope.friends, function (friend) { friend.age = parseFloat(friend.age); });
It should work,
See PLunker