SuMthing.

Trace or tap five to eight tiles in equation order. You can turn corners and start anywhere. Move horizontally or vertically, using each tile once.

Use standard order of operations. For example, 2+3×4=14 fits in eight tiles. A valid equation can still be a decoy. The right set fills the whole board without overlaps.

Drag to add a valid snake when you release. If you tap tiles, use Add snake. Tap a lone selected tile again to deselect it. Tap the previous tile to backtrack. A hint checks for a decoy before revealing a snake.

Keyboard: Tab to the board, use arrows to move between tiles, and press Space to select.