
theorem Th1104:
Sum digits(725,10) = 14
proof
  thus Sum digits(725,10) = Sum <%5,2%>+Sum <%7%> by Th1103,AFINSQ_2:55
  .= (5 + 2) + Sum <%7%> by AFINSQ_2:54
  .= 7 + 7 by AFINSQ_2:53
  .= 14;
end;
