
theorem Th974:
Sum digits(736,10) = 16
proof
  thus Sum digits(736,10) = Sum <%6,3%>+Sum <%7%> by Th973,AFINSQ_2:55
  .= (6 + 3) + Sum <%7%> by AFINSQ_2:54
  .= 9 + 7 by AFINSQ_2:53
  .= 16;
end;
