Complete the number analogy: 72 : 45 :: 96 : ?

The number is written the other way about and that reversal is taken away from it. For 72 the reversal is 27, and 72 − 27 = 45; for 96 the reversal is 69, and 96 − 69 = 27. The trap 165 adds the reversal instead of subtracting it, but 72 + 27 = 99 and not 45. 69 stops at the bare reversal, which on the first pair would have answered 27 rather than 45, and 54 is the product of the digits, $6\times 9$, where $7\times 2=14$.