
theorem Th946:
Sum digits(299,10) = 20
proof
  thus Sum digits(299,10) = Sum <%9,9%>+Sum <%2%> by Th945,AFINSQ_2:55
  .= (9 + 9) + Sum <%2%> by AFINSQ_2:54
  .= 18 + 2 by AFINSQ_2:53
  .= 20;
end;
