
theorem Th165:
Sum digits(266,10) = 14
proof
  thus Sum digits(266,10) = Sum <%6,6%>+Sum <%2%> by Th164,AFINSQ_2:55
  .= (6 + 6) + Sum <%2%> by AFINSQ_2:54
  .= 12 + 2 by AFINSQ_2:53
  .= 14;
end;
