Subtraction is a mathematical operation that represents the operation of removing objects from a collection. It is signified by the minus sign (-). For example, in the picture on the right, there are 5 - 2 apples—meaning 5 apples with 2 taken away, which is a total of 3 apples. Therefore, 5 - 2 = 3. Besides counting fruits, subtraction can also represent combining other physical and abstract quantities using different kinds of objects including negative numbers, fractions, irrational numbers, vectors, decimals, functions, and matrices.