
theorem Th583:
Sum digits(2540,10) = 11
proof
  thus Sum digits(2540,10) = Sum <%0,4,5%>+Sum <%2%> by Th582,AFINSQ_2:55
  .= Sum <%0,4%> + Sum <%5%> + Sum <%2%> by AFINSQ_2:55
  .= (0 + 4) + Sum <%5%> + Sum <%2%> by AFINSQ_2:54
  .= (0 + 4 + 5) + Sum <%2%> by AFINSQ_2:53
  .= 9 + 2 by AFINSQ_2:53
  .= 11;
end;
