
theorem Th1116:
Sum digits(925,10) = 16
proof
  thus Sum digits(925,10) = Sum <%5,2%>+Sum <%9%> by Th1115,AFINSQ_2:55
  .= (5 + 2) + Sum <%9%> by AFINSQ_2:54
  .= 7 + 9 by AFINSQ_2:53
  .= 16;
end;
