Also known as Muggins or Fives-Up: dominoes where the maths matters. Every time the two open ends of the line add up to a multiple of five, you score that many points instantly.
Rules
You and the AI each draw seven tiles from a shuffled double-six set, with the rest forming a boneyard.
On your turn, tap a highlighted tile to play it against either open end — a double on an end counts BOTH its halves toward the ends total.
Whenever the two open ends sum to a multiple of five, you score that many points immediately. If you have no playable tile, you draw from the boneyard until you can (or must pass if it runs out).
Empty your hand first to win the hand and collect your opponent’s leftover pips (rounded to the nearest five). First to 100 points wins the match.
Tips
5–5 opens for 10 and 6–4 opens for 10 too. Watch the running end total — play tiles that push it to a multiple of five, and deny the AI the same.