
theorem Th926:
Sum digits(69,10) = 15
proof
  thus Sum digits(69,10) = Sum <%9%>+Sum <%6%> by Th925,AFINSQ_2:55
  .= 9 + Sum <%6%> by AFINSQ_2:53
  .= 9+6 by AFINSQ_2:53
  .= 15;
end;
