
theorem Th240:
Sum digits(204,10) = 6
proof
  thus Sum digits(204,10) = Sum <%4,0%>+Sum <%2%> by Th239,AFINSQ_2:55
  .= (4 + 0) + Sum <%2%> by AFINSQ_2:54
  .= 4 + 2 by AFINSQ_2:53
  .= 6;
end;
