thus Sum (digits (2332,10)) = (Sum <%2,3,3%>) + (Sum <%2%>) by Th912, AFINSQ_2:55
.= ((Sum <%2,3%>) + (Sum <%3%>)) + (Sum <%2%>) by AFINSQ_2:55
.= ((2 + 3) + (Sum <%3%>)) + (Sum <%2%>) by AFINSQ_2:54
.= ((2 + 3) + 3) + (Sum <%2%>) by AFINSQ_2:53
.= 8 + 2 by AFINSQ_2:53
.= 10 ; :: thesis: verum