NMBR 9 ++ includes four sets of numbers 0-9, as well as twenty number cards (0-9 twice), so with this box you can play NMBR 9 with only two players. Alternatively, if you already have NMBR 9, you can now play the game with up to six players at once.

NMBR 9 ++ also includes expansion components that you can use with this box or with the original NMBR 9 game or with both combined. You have six different starting tiles, for example, with each player taking one at random before the game begins, which makes it impossible for players to build in the same patterns as one another.

You can give each player two "gap filler" tiles — one that is a single square and a second that is two squares long. You can use one or both at any point in the game when you're placing a number tile.

You can deal out two of the six "rule breaker" cards, then give each player two cubes in a different color. During the game, if you want to use a "rule breaker" card — e.g., move a tile previously placed, place the current tile upside down, or reserve the tile for placement later — place one of your cubes on the card, then use its power. You can use each card only once.

Finally, NMBR 9 ++ includes variant rules that can be used with 1-4 players. In "2 out of 3", you create a deck of thirty cards (0-9 thrice) and put all of the number tiles on the table. Each round, you reveal three cards one by one. Each player can place the first number tile revealed or refuse it; if they refuse it, they must place the next two number tiles; if they place it, they must refuse one of the next two tiles. In the end, everyone will place twenty number tiles, as in the basic game.

In "Level to Level", shuffle all forty cards into a deck, place all number tiles on the table, and lay out new tokens numbered 0-4. For the first two turns, draw a card and placed it under 0; each player must place this number tile in front of them following the usual rules. For the third turn, flip a card into both the 0 slot and 1 slot; the tile showing under 0 can be placed only on the ground level and the tile under 1 can be placed only on the first level. You can refuse to place either or both tiles.

Once a player has two tiles on the first level, next turn flip a card under slots 0, 1, and 2, with the latter number tile being placed only on the second level. Continue play until the deck runs out or you can't flip enough cards to start a turn.