Mahjong Math

The faces in Mahjong Math carry numbers and short arithmetic expressions instead of suits. A pair is valid when the two tiles come to the same value, so a tile reading twelve can be taken with another twelve or with one showing a sum that works out to twelve.

That turns the usual pattern recognition into arithmetic under no particular pressure. There is no clock at all, and an undo sits alongside the hint, which makes this one of the few boards where an experimental match costs nothing. Mahjong Alchemy asks the same question of a taller pile.

A hundred and sixty-eight layouts are included, so the arrangement changes long before the arithmetic gets stale. The clearing rule stays orthodox: only free tiles can be taken, so the numbers you want are usually under the ones you do not. One more board from the same group is the Connect grid.

The 2012 HTML5 build works with a mouse or a tap, on desktop and mobile. Full screen is worth it because the numerals and expressions are printed small, and misreading a value here costs a move rather than a tile. Only tiles with an open side move in the Jolly Jong Journey board too.

1. Pick two free tiles whose values are equal, as plain numbers or as a small sum.
2. Click one, then the other, and the matching values clear.
3. Use the undo if a match turns out badly; nothing is timed.
4. Clear the whole layout to finish, then move on to another arrangement.

• Do the arithmetic before you click — Mahjong Math is quiet enough that a careless sum is the only real mistake available.
• Use undo as a probe — with no clock running, testing a match and reversing it is free.
• Clear the top layers — a number buried under another tile cannot be counted, let alone paired.
• Group by value, not by look — two tiles that read nothing alike can still be worth the same.
• Switch to full screen — expressions printed small are easy to misread at a glance.