Four Operations is a free, print-and-play card deck that can be used for designing and playing a wide assortment of math games. It includes 54 cards, numbered 1-9 in six suits: rain, clouds, leaves, clovers, fish, and butterflies. The six suits are divided into three colors: gray for the weather suits, green for the plant suits, and purple for the animal suits. Each card has a number in the center, surrounded on the edges by the four basic operations. The deck is designed to support a variety of mechanics and scoring systems and allows for the use of negative numbers.