
theorem Th1102:
Sum digits(675,10) = 18
proof
  thus Sum digits(675,10) = Sum <%5,7%>+Sum <%6%> by Th1101,AFINSQ_2:55
  .= (5 + 7) + Sum <%6%> by AFINSQ_2:54
  .= 12 + 6 by AFINSQ_2:53
  .= 18;
end;
