Fill in the blanks: (i) The product of two positive rational numbers is always ............... . (ii) The product of two negative rational numbers is always ............... . (iii) If two rational numbers have opposite signs then their product is always ............... . (iv) The reciprocal of a positive rational number is ............... and the reciprocal of a negative rational number is ............... . (v) Rational number 0 has ............... reciprocal. (vi) The product of a non-zero rational number and its reciprocal is ............... . (vii) The numbers ............... and ............... are their own reciprocals. (viii) If is reciprocal of , then the reciprocal of is ............... .