Problems with AngularJS in ng-repeat in IE9

Firefox and Chrome work like a charm, only IE9 is annoying again. I use these code snippet:

<div class="weekDays-sliders" fixed="0">
    <div class="weekDays-slider" style="left: {{30+($index*485)}}px;" ng-repeat="week in searchResult.weeks">
        <div class="weekDay" ng-repeat="day in week.days">
            <div class="weekDay-name">{{day.name}}</div>
            <div class="weekDay-date">{{day.date}}</div>
        </div>
    </div>
</div>

With {{30+($index*485)}} i calculate the right position for the div. They are all side by side. The problem is that the IE ignore that. The IE not even add a style-attribute. (see screen)

enter image description here

Whats the problem here, how can i solve these?

with ng-style it work like expected

ng-style="{'left': 30+($index*485)+'px'}"