
theorem Th986:
Sum digits(897,10) = 24
proof
  thus Sum digits(897,10) = Sum <%7,9%>+Sum <%8%> by Th985,AFINSQ_2:55
  .= (7 + 9) + Sum <%8%> by AFINSQ_2:54
  .= 16 + 8 by AFINSQ_2:53
  .= 24;
end;
