Original: Here, the identity element is 1, since 1 Ã - a = a Ã - 1 = a for any rational number a/O. The inverse of a is 1\/a, since a Ã - 1\/a = 1.
Simplified: When the number is 1, then the 1 is not written because 1 times any number is that number (1 Ã - y = y) and so is not needed.