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