
theorem Th405:
Sum digits(740,10) = 11
proof
  thus Sum digits(740,10) = Sum <%0,4%>+Sum <%7%> by Th404,AFINSQ_2:55
  .= (0 + 4) + Sum <%7%> by AFINSQ_2:54
  .= 4 + 7 by AFINSQ_2:53
  .= 11;
end;
