Introduction and Goal of the game
Summy is a game of Cwali (Corné van Moorsel) and is some kind of Scrabble for Sums. Players get points in their turns for making a sum in their turn. These Sums have to be made with numbers and numerical operators. You can only make sums with (a part of) your pieces, if you make a valid Sum in combination with other pieces already on the board. The Sum has to be complete and you cannot remove pieces from the board or move pieces. After your turn you get randomly new pieces for the pieces you put on the board. Below is an image of a completed game of Summy.
There are 129 numbers and numerical operator in the game:
8 times the 0, 1, 2, 3, 4, 5, 6, 7, 8, 9 and 7 times the '-', the '+', the ':' and the 'x'.
19 times the '='.
In the middle of the 25x25 board a '=' is put down. Both player get randomly 8 pieces, the rest of the 110 pieces are kept as stock. Your opponent has no knowledge of your pieces. Click on a piece above the board to select it and then click on the board to place it on the board. If you want to remove a piece from the board, click it again.
The following rules apply for a complete sum:
Sums are read from left to right or from top to bottom.
There is exactly one '=' in the sum.
The pieces of the sum form a straight line without any interruption.
Behind the '=' -sign there is only a single number (consisting out of 1 or more digits).
Before the '=' -sign there have to be 2 or more numbers (each consisting out of 1 or more digits) with in between '+', '-', 'x' or ':' .
The standard order of operations apply, see Wikipedia. Multiplication and division precede addition and subtraction. When two operators have the same precedence, then work from the left to right. For example the Sum: '70+118:2=129' is valid. (This example sum consists of 12 pieces, so a minimal of 4 pieces was already on the board, this is rare!)
A number may not have a leading 0, so 15+12=027 is not valid. 8-8=0 of course is valid.
Before and after every complete Sum a grey piece is put on the board.
Parts of Sums
When making sums on the board, the pieces in other directions can make valid sums or parts of sums. Complete sums also give points. If you lay down a part of a Sum also, no rules apply. Tiles can be put in any order (this rule has change on december 2, 2009).
You get points for every complete sum. The points are equal to all digits (0-9) in the sum. The sum '2x3=6' gives 11 points (2+3+6). The sum'65+2x0=65' gives 24 points (6+5+2+0+6+5). The sum '5+74=79' is worth 32 points (5+7+4+7+9).
If you cannot or do not want to make a valid sum, you can use your turn to exchange pieces. The pieces you exchange are put away (and not back into the stock). You get the same amount of new pieces back (randomly) if there are still pieces in stock.
End of the game
As soon as a player 4 or less pieces has left (after his turn), this player has made his last move and only his opponent can make one more last move. After that the game ends, the player with the most points, wins the game.