Question mark in a box is a symbol that is used to represent an unknown or uncertain value. It is typically displayed as a white question mark inside a black box. The question mark in a box is often used in mathematics and science to indicate that a value is not known or cannot be determined. For example, in the equation x + y = ?, the question mark in the box represents the unknown value of y.
The question mark in a box can also be used in other contexts, such as in computer programming and logic. In computer programming, the question mark in a box is often used to represent a null value. In logic, the question mark in a box is often used to represent an unknown or uncertain proposition.
