
theorem Th1057:
Sum digits(624,10) = 12
proof
  thus Sum digits(624,10) = Sum <%4,2%>+Sum <%6%> by Th1056,AFINSQ_2:55
  .= (4 + 2) + Sum <%6%> by AFINSQ_2:54
  .= 6 + 6 by AFINSQ_2:53
  .= 12;
end;
