Question 1112408
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{{{root(3,720)}}} = 8.96 (approximately).


Therefore, the number under the question should be close to 8.96 from the lower side.


Inspired by this observation, I write  720 = 8*9*10,  using factors that are close to 8.96.


From this decomposition, it is clear that the answer is 8.
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Solved.