
theorem Th685:
Sum digits(3560,10) = 14
proof
  thus Sum digits(3560,10) = Sum <%0,6,5%>+Sum <%3%> by Th684,AFINSQ_2:55
  .= Sum <%0,6%> + Sum <%5%> + Sum <%3%> by AFINSQ_2:55
  .= (0 + 6) + Sum <%5%> + Sum <%3%> by AFINSQ_2:54
  .= (0 + 6 + 5) + Sum <%3%> by AFINSQ_2:53
  .= 11 + 3 by AFINSQ_2:53
  .= 14;
end;
