
theorem Th401:
Sum digits(700,10) = 7
proof
  thus Sum digits(700,10) = Sum <%0,0%>+Sum <%7%> by Th400,AFINSQ_2:55
  .= (0 + 0) + Sum <%7%> by AFINSQ_2:54
  .= 7 by AFINSQ_2:53;
end;
