The logic to this series is as follows;

2 x 2 – 1 = 4 – 1 = 3;

4 x 4 – 3 = 16 – 3 = 13;

8 x 6 – 5 = 48 – 5 = 43;

10 x 8 – 7 = 80 – 7 = 73;

Therefore we can find the answer as;

12 x 10 – 9 = 120 – 9 = 111

Missing next number = 111

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