
theorem Th179:
Sum digits(16,10) = 7
proof
  thus Sum digits(16,10) = Sum <%6%>+Sum <%1%> by Th178,AFINSQ_2:55
  .= 6 + Sum <%1%> by AFINSQ_2:53
  .= 6+1 by AFINSQ_2:53
  .= 7;
end;
