(i) For an integer a, the multiplicative inverse is 1a.
This is the definition of multiplicative inverse. So, this is correct.
(ii) The product of an integer and its multiplicative inverse is 1.
a × 1a =1. So, this is also correct.
(iii) Multiplicative inverse of 67 is 167.
Multiplicative inverse of -67 is −167. So, this is incorrect.
(iv) The integers 1 and -1 are equal to their resepective multiplicative inverse.
Multiplicative inverse of 1 is 1 and that of -1 is -1. So, this is correct.
Hence, statements (i), (ii) and (iv) are correct.