DB::statement(DB::raw('SET @rownum = 0'));

$tops = DB::table('articles')
    ->select(DB::raw('id','head','description', '@rownum := @rownum + 1 as rownum'))
    ->where('approve', '=', 'Aprobado')
    ->where('important','Destacado')
    ->orderBy('id', 'DESC')
    ->paginate(5);

<div id="tops0" class="card" style="border:none !important; margin: 0;">
        <a href="{{ route('show',$top->id.$top->head) }}">
            <img  class="card-img-top" src="../images/{{$top->path}}" alt="Card image cap" style="height: 112px">
        </a>
        <a href="{{ route('show',$top->id.$top->head) }}" class="a-corregido2">
            <span id="">{{$top->rownum}}</span><span class="title-tops">{{ $top ->head }}</span>
        </a>
    </div>


@endforeach