
theorem Th775:
Sum digits(616,10) = 13
proof
  thus Sum digits(616,10) = Sum <%6,1%>+Sum <%6%> by Th774,AFINSQ_2:55
  .= (6 + 1) + Sum <%6%> by AFINSQ_2:54
  .= 7 + 6 by AFINSQ_2:53
  .= 13;
end;
