
theorem Th585:
Sum digits(2560,10) = 13
proof
  thus Sum digits(2560,10) = Sum <%0,6,5%>+Sum <%2%> by Th584,AFINSQ_2:55
  .= Sum <%0,6%> + Sum <%5%> + Sum <%2%> by AFINSQ_2:55
  .= (0 + 6) + Sum <%5%> + Sum <%2%> by AFINSQ_2:54
  .= (0 + 6 + 5) + Sum <%2%> by AFINSQ_2:53
  .= 11 + 2 by AFINSQ_2:53
  .= 13;
end;
