
theorem Th298:
Sum digits(228,10) = 12
proof
  thus Sum digits(228,10) = Sum <%8,2%>+Sum <%2%> by Th297,AFINSQ_2:55
  .= (8 + 2) + Sum <%2%> by AFINSQ_2:54
  .= 10 + 2 by AFINSQ_2:53
  .= 12;
end;
