1×31

1×31 denotes the product of the integers 1 and 31, yielding 31. This simple expression demonstrates the multiplicative identity: multiplying a number by 1 leaves it unchanged. In general, for any number a, 1×a = a and a×1 = a. The identity property is a fundamental principle in arithmetic and algebra and underpins many simplifications and computations. The commutative property of multiplication also applies here, since 1×31 = 31×1.

The number 31 itself is prime, meaning its only positive divisors are 1 and 31. Its prime factorization consists solely of 31. In base 2, 31 is represented as 11111. In decimal notation, it is written as the two digits 3 and 1, and it is known as the 11th prime number.

Beyond its role in this particular product, the rule 1×a = a is widely used to preserve values in algebraic manipulation, programming, and numerical computing. It also serves as a basic building block for more complex identities and equations, where maintaining the value of expressions during transformation is essential.