
theorem Th1040:
Sum digits(1610,10) = 8
proof
  thus Sum digits(1610,10) = Sum <%0,1,6%>+Sum <%1%> by Th1039,AFINSQ_2:55
  .= Sum <%0,1%> + Sum <%6%> + Sum <%1%> by AFINSQ_2:55
  .= (0 + 1) + Sum <%6%> + Sum <%1%> by AFINSQ_2:54
  .= (0 + 1 + 6) + Sum <%1%> by AFINSQ_2:53
  .= 7 + 1 by AFINSQ_2:53
  .= 8;
end;
