thus Sum (digits (1034,10)) = (Sum <%4,3,0%>) + (Sum <%1%>) by Th806, AFINSQ_2:55
.= ((Sum <%4,3%>) + (Sum <%0%>)) + (Sum <%1%>) by AFINSQ_2:55
.= ((4 + 3) + (Sum <%0%>)) + (Sum <%1%>) by AFINSQ_2:54
.= ((4 + 3) + 0) + (Sum <%1%>) by AFINSQ_2:53
.= 7 + 1 by AFINSQ_2:53
.= 8 ; :: thesis: verum