
theorem Th379:
Sum digits(480,10) = 12
proof
  thus Sum digits(480,10) = Sum <%0,8%>+Sum <%4%> by Th378,AFINSQ_2:55
  .= (0 + 8) + Sum <%4%> by AFINSQ_2:54
  .= 8 + 4 by AFINSQ_2:53
  .= 12;
end;
