
theorem Th228:
Sum digits(68,10) = 14
proof
  thus Sum digits(68,10) = Sum <%8%>+Sum <%6%> by Th227,AFINSQ_2:55
  .= 8 + Sum <%6%> by AFINSQ_2:53
  .= 8+6 by AFINSQ_2:53
  .= 14;
end;
