The author of Summy requested us to change the rules for Summy. These changes are effectively immediatly for new games as well as running games.
New games get more numbers (7 of each instead of 6), more operators (7 each instead of 6) and more = signs (21 instead of 18).
The rule about parts of sums you lay down as well in other directions is removed. There are no more rules for that.
Update december 14, 2009: small change again, now you have 8 numbers from 0 till 9.