Array of Array

I have a function for add data and I can add data but when I try to put this array in ion-card with *ngFor like:

<ion-card *ngFor="let x of tudo; let i = index">
      <ion-card-header>
         <ion-card-title>Parte {{i+1}}</ion-card-title>
     </ion-card-header>

    <ion-card-content>
       <ion-label>Divisão: {{x.divisao}}</ion-label><br>
       <ion-label>Figura: {{x.figura}}</ion-label><br>
       <ion-label>Tempo: {{x.tempo}}</ion-label><br>
       <ion-label>Quantidade: {{x.quantidade}}</ion-label><br>
   </ion-card-content>
</ion-card>

When I load page:
Error: Uncaught (in promise): Error: Cannot find a differ supporting object ‘[object Object]’ of type ‘object’. NgFor only supports binding to Iterables such as Arrays.
Error: Cannot find a differ supporting object ‘[object Object]’ of type ‘object’. NgFor only supports binding to Iterables such as Arrays.