
theorem Th211:
Sum digits(384,10) = 15
proof
  thus Sum digits(384,10) = Sum <%4,8%>+Sum <%3%> by Th210,AFINSQ_2:55
  .= (4 + 8) + Sum <%3%> by AFINSQ_2:54
  .= 12 + 3 by AFINSQ_2:53
  .= 15;
end;
