いちごカレンダー (Strawberry Calendar)

いちごカレンダー (Strawberry Calendar) is a Japanese game using mathematics.

You are allowed to eat strawberries only on the 15th of each month. Players manipulate the calendar using maths to make today appear to be the 15th, so they can eat strawberries.

The game has a deck of red cards for the days of the month 1 to 31, and a small deck of green cards for the arithmetic functions + - × ÷ and =. Players use these cards to get to a result of 15.

The game is designed to encourage players to use mental arithmetic as they play.

user summary

１日〜31日のうち、真ん中にあるいちご（１５）の日。どんな日でもいちごが食べられるよに、四苦八苦してなんとか15（いちご）の日にしよう。いちご（１５）作りには、+.-.×.÷を使うことができます。遊びながら算数ドリのように暗算を繰り返すゲーム。 publisher's summary