|How Many? is a two-player micro-deduction game in which players hold four cards "backwards" — that is, facing the other player, as in Hanabi — and take turns asking questions about the numbers visible at the top of their cards. Possible actions in the game are:
1) Guess a number for any two cards in your hand. Your opponent answers more/less/exact number.
2) Once per game, you can rotate a card in your opponent's hand to change the number value.
3) Guess the sequence of numbers on the cards in your hand; guess correctly, and you win.