
theorem Th799:
Sum digits(946,10) = 19
proof
  thus Sum digits(946,10) = Sum <%6,4%>+Sum <%9%> by Th798,AFINSQ_2:55
  .= (6 + 4) + Sum <%9%> by AFINSQ_2:54
  .= 10 + 9 by AFINSQ_2:53
  .= 19;
end;
