
theorem Th193:
Sum digits(240,10) = 6
proof
  thus Sum digits(240,10) = Sum <%0,4%>+Sum <%2%> by Th192,AFINSQ_2:55
  .= (0 + 4) + Sum <%2%> by AFINSQ_2:54
  .= 4 + 2 by AFINSQ_2:53
  .= 6;
end;
