.aufgaben_desc {
  display: flex;
  justify-content: center; /* horizontally centers the images */
  align-items: center; /* vertically centers the images */
}

.aufgaben_desc img {
    width: 30%; /* sets the width of the images */
    padding-left: 5px;
    padding-right: 5px;
}

.icon {
    margin-bottom: -5px; 
    margin-left : 5px;
    margin-right : 5px;
    display: inline;
    width : 20px;
}