Place cards in a 4x4 grid. Try to make rows/columns that add up to 21.
Totally free. No in-app purchases.
A row/column will clear under the following circumstances:
A) Adds up to 21. Score a point.
B) Bust - Sum over 21. No point.
C) When a row or column is full.
You have one pass through the deck to make as many 21s as you can.