
theorem Th197:
Sum digits(272,10) = 11
proof
  thus Sum digits(272,10) = Sum <%2,7%>+Sum <%2%> by Th196,AFINSQ_2:55
  .= (2 + 7) + Sum <%2%> by AFINSQ_2:54
  .= 9 + 2 by AFINSQ_2:53
  .= 11;
end;
