Question 452389: My grandaughter came home with six of these math problems (6th grade)....
Using the numbers (2,3,4,5,7,8,9) fill in the blanks.
_*_-_/_+_*_/_=3
Using brute force it took me (and four other ADULTS) several hours to answer all 6 questions....
Am I missing something here?? Is there some technique I am missing?
Found 2 solutions by Alan3354, richard1234:
Answer by Alan3354(69443)   (Show Source):
You can put this solution on YOUR website! Trial and error is the only way.
The only possible use for such problems is ... not sure what.
I don't see the point or the purpose of problems like this.
Answer by richard1234(7193)  (Show Source):
You can put this solution on YOUR website! It is impossible to obtain 3 using all the digits once, assuming the order of operations is followed.
Suppose the integers are a,b,...g in that order, with
This implies
The maximum value the RHS can attain is when c = 9, d = 2, in which RHS = 15/2. If this is the case, ab must be greater than or equal to 3*4 = 12, in which this is impossible. In all other cases, the maximum value of the RHS is smaller than the minimum value of the LHS, implying that equality is impossible to obtain.
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