thus Sum (digits (2460,10)) = (Sum <%0,6,4%>) + (Sum <%2%>) by Th574, AFINSQ_2:55
.= ((Sum <%0,6%>) + (Sum <%4%>)) + (Sum <%2%>) by AFINSQ_2:55
.= ((0 + 6) + (Sum <%4%>)) + (Sum <%2%>) by AFINSQ_2:54
.= ((0 + 6) + 4) + (Sum <%2%>) by AFINSQ_2:53
.= 10 + 2 by AFINSQ_2:53
.= 12 ; :: thesis: verum