(17) < 18, that is, 18- 1= 17, you can fill in the number between 17 and 0.

(15) > 14, that is, 14+ 1= 15. Numbers between 0 and 14 cannot be filled in, but numbers within 15 can be filled in.

(15)= 15, that is, 15+0 = 15,15 =15. The answer is the number itself.

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