81×1

81×1 denotes the product of eighty-one and one in the decimal system. It is a basic example of the identity property of multiplication, which states that any number multiplied by one equals the number itself. Therefore, 81×1 equals 81.

This identity holds for all numbers and is widely used in arithmetic, algebra, and computer science as a simplification rule. The number 81 itself is a perfect square (9×9) and can be expressed as 3^4; its multiplication by 1 does not change its value.

In the context of multiplication tables or algebraic expressions, 81×1 emphasizes that the unit element for multiplication is one.