<h1>90%+ fail to answer "missing number"</h1>

An excellent puzzle to practice "find the missing number"

90% plus fail to answer.

Brain teasers and puzzles
Questionnaire "missing number"Try to solve it.

Math reasoning questions for just a few fans.
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 The puzzle is very difficult to find the missing number and the logical relation of the equations. 

 You can check your answer and see the detailed explanation in mathematical reasoning.



Solutions
The correct answer is 72

AB=A!/B!
97=9!/7!= 1.2.3.4.5.6.7.8.9/1.2.3.4.5.6.7=8.9=72