In a × 1 = a = 1 × a and ∀ a ∈ R then '1' is called?

In a × 1 = a = 1 × a and ∀ a ∈ R then '1' is called?

Explanation

The number 1 is called the multiplicative identity because multiplying any real number a by 1 leaves it unchanged: a × 1 = 1 × a = a.

This property holds for all real numbers (∀ a ∈ R).