
theorem Th395:
Sum digits(640,10) = 10
proof
  thus Sum digits(640,10) = Sum <%0,4%>+Sum <%6%> by Th394,AFINSQ_2:55
  .= (0 + 4) + Sum <%6%> by AFINSQ_2:54
  .= 4 + 6 by AFINSQ_2:53
  .= 10;
end;
