👉 Tripenny is a type of mathematical puzzle that involves solving for the value of an unknown variable in a sequence. It was first proposed by mathematician and philosopher Arthur Cayley in 1865, and it has since become one of the most popular and well-known puzzles in mathematics. In the context of tripenny, the goal is to determine the value of the variable "x" that satisfies the equation: \[ x + 2 = 3 \] The solution to this equation is