<div class="col-md-3">
    <h1>Content</h1>
</div>
<div class="col-md-3">
    <h1>Content</h1>
</div>
<div class="col-md-3">
    <h1>Content</h1>
</div>
<div class="col-md-3">
    <h1>Content</h1>
</div>

<div class="col-md-4">
    <h1>Content</h1>
</div>
<div class="col-md-4">
    <h1>Content</h1>
</div>
<div class="col-md-4">
    <h1>Content</h1>
</div>

<div class="col-md-6">
    <h1>Content</h1>
</div>
<div class="col-md-6">
    <h1>Content</h1>
</div>

<div class="col-md-12">
    <h1>Content</h1>
</div>

$scope.number = 4;//your column count
$scope.getNumber = function(num) {
    return new Array(num);
}

<div ng-repeat="i in getNumber(number) track by $index" class="col-sm-{{12/number}}">
     <h1>Content</h1>
</div>