
theorem Th1112:
Sum digits(850,10) = 13
proof
  thus Sum digits(850,10) = Sum <%0,5%>+Sum <%8%> by Th1111,AFINSQ_2:55
  .= (0 + 5) + Sum <%8%> by AFINSQ_2:54
  .= 5 + 8 by AFINSQ_2:53
  .= 13;
end;
