Can ng-model update another ng-model? - angularjs

Question

This is my code:
<table ng-init="liveTotal={}">
<tr ng-repeat="x in sovCtrl.topics" >
<td> {{x}}</td>
<td><input ng-model="sovCtrl.objects[x]" type="number"></td>
<td ng-hide="true">
<input ng-model="liveTotal[$index]" type="number" value="{{sovCtrl.objects[x]}}">
</td>
</tr>
</table>
<div > Current Result:
{{ 0 + liveTotal[0] + liveTotal[1] + liveTotal[2] + liveTotal[3] + liveTotal[4]}}
</div>
What I'm trying to do is have a live result of the sum of all the Inputted topic values(there will never be more than 5) without using $scope or any extra sovCtrl methods/objects or adding a script;
The topics are strings I can't predict.
The 2nd input CHANGES when I type into the first input, but the result in the div does not.
The result in the div changes only when I type or press on the 2nd input(if I make it visible)
Can this be done using angular but modifying only the above HTML?
Edit: sovCtrl.objects gets passed into functions that graph the values. Modifying the the keys would break those functions.

Answer 1

Why don't you directly do something like shown below
wherein you directly use the first input
You just add an index (which is provided in ng-repeat of any variable) and now you can access values by using index 0,1,2,3,4
<table ng-init="liveTotal={}">
<tr ng-repeat="(i,x) in sovCtrl.topics" >
<td> {{x}}</td>
<td><input ng-model="sovCtrl.objects[x]" ng-change="sovCtrl.objects_yo[i]=sovCtrl.objects[x]" type="number"></td>
</tr>
</table>
<div> Current Result:
{{ 0 + sovCtrl.objects_yo[0] + sovCtrl.objects_yo[1] + sovCtrl.objects_yo[2] + sovCtrl.objects_yo[3] + sovCtrl.objects_yo[4]}}
</div>

Answer 2

Got it, this works.
<table ng-init="liveTotal={}">
<tr ng-repeat="x in sovCtrl.topics" >
<td> {{x}}</td>
<td><input ng-model="sovCtrl.objects[x]" type="number"></td>
<td ng-show="false"> {{ liveTotal[$index]= sovCtrl.shareOfVoice[x]}}</td>
</tr>
</table>
<div > Current Result:
{{ 0 + liveTotal[0] + liveTotal[1] + liveTotal[2] + liveTotal[3] + liveTotal[4]}}
</div>