
theorem Th791:
Sum digits(814,10) = 13
proof
  thus Sum digits(814,10) = Sum <%4,1%>+Sum <%8%> by Th790,AFINSQ_2:55
  .= (4 + 1) + Sum <%8%> by AFINSQ_2:54
  .= 5 + 8 by AFINSQ_2:53
  .= 13;
end;
