thus Sum (digits (4600,10)) = (Sum <%0,0,6%>) + (Sum <%4%>) by Th1345, AFINSQ_2:55
.= ((Sum <%0,0%>) + (Sum <%6%>)) + (Sum <%4%>) by AFINSQ_2:55
.= ((0 + 0) + (Sum <%6%>)) + (Sum <%4%>) by AFINSQ_2:54
.= ((0 + 0) + 6) + (Sum <%4%>) by AFINSQ_2:53
.= 6 + 4 by AFINSQ_2:53
.= 10 ; :: thesis: verum