Forty-one new levels are waiting to be solved.
Need more? Create your own with the level editor!

The game objective is to set value of target tiles to zero by placing subtraction tiles in the right positions. Blue circles decrease the value of target tiles in diagonal directions while red squares subtract values in horizontal and vertical directions.

Editor description
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Arrange target tiles and sum point tiles on the game field.
Use [T], [H] and [D] buttons to select corresponding tiles or use keys: Q, W, E.
To delete tiles click the [X] button or press R and then click on tiles to remove.
Use the [-] and [+] buttons to set values or use the mouse wheel or keys: 1-9, A, S.

Press the Load button to load a previously saved level. The Save button doesn't save the level to your system. It creates a restore point during the editing session. To load a custom level, copy its code to the 'LEVEL CODE' input field at the top of the screen and press Load.

To test a level press the Play button. If the level is passable it's code will appear at the top of the screen under the 'LEVEL CODE' input field. Select and copy the code from there. The blue string at the bottom of screen shows the latest completed level.
Controls

GAME:
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MOUSE,
KEYS:
Z, Space, Backspace - Undo last move
R, Enter, Down - Restart Game
F1 - Show help (levels 1-7)
Esc - Main Menu
M, S - Music / Sound
L, Up - Select Level
Left, Right - Prev / Next Level

EDITOR:
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A, S, 1-9, Mouse Wheel - Change Value
Q, W, E, R, Tab - Switch Tiles
Arrows - Move Tiles
Enter - Test Level