
theorem Th765:
Sum digits(506,10) = 11
proof
  thus Sum digits(506,10) = Sum <%6,0%>+Sum <%5%> by Th764,AFINSQ_2:55
  .= (6 + 0) + Sum <%5%> by AFINSQ_2:54
  .= 6 + 5 by AFINSQ_2:53
  .= 11;
end;
