Zero21 Solitare

1. Click a card to take it off the board — its value moves the running total up or down.
2. Never let the total go below 1 or above 20.
3. Put a card aside in HOLD and use it later.
4. Spend diamonds to put a card in the trash, and clear the board to finish the level.

Zero21 Solitare is a solitaire game built on mental arithmetic. Every card has a number, and clicking one takes it off the board and changes a running total by that amount, up or down. Your job is to clear the whole board without ever letting that total drop below one or climb above twenty. The HOLD spot lets you park a card to play later, which is often the difference between a clean finish and a dead end, and diamonds earned by clearing levels can pay to throw an awkward card in the trash. Looking a few cards ahead and saving big numbers for when the total has room makes each level much easier.