Edit in JSFiddle

var app = angular.module("kalkulator", []);
app.controller("kalkulatorController", function ($scope) {
    $scope.angka1 = 0;
    $scope.angka2 = 0;
});
<div data-ng-app="kalkulator">
    <div data-ng-controller="kalkulatorController">Angka 1:
        <input type="number" ng-model="angka1">
        <br />Angka 2:
        <input type="number" ng-model="angka2">
        <br/>{{angka1}} + {{angka2}} = {{angka1+angka2}}
        <br/>{{angka1}} - {{angka2}} = {{angka1-angka2}}
        <br/>{{angka1}} * {{angka2}} = {{angka1*angka2}}
        <br/>{{angka1}} / {{angka2}} = {{angka1/angka2}}
        <br/>
    </div>
</div>