12345678 can only be used once per number 1 9 2 7

Adding = 7 must be.

an odd number and an even number;

If you add = 9, it must be.

an odd number and an even number;

Subtraction = 1, it must be.

an odd number and an even number;

Subtraction = 2, it must be.

Two odd numbers. Or.

two even numbers; There are topics.

4 pcs. odd number, 4 even numbers, and above.

Request. 3 odd numbers.

Or. 5 odd numbers. Not at all.

If yes. iq

If you want to ask, the mystery of the question should be there.

Article 2. +=9, actually.

6 = () + in reverse is the solution:

Under normal circumstances, there is no solution to this problem. But in the field of brain teasers, it can still be solved.

If you turn the second equation upside down, it becomes 6=( ).

The last equation becomes (7)+(=7, so that 3 is omitted. Brain teasers are still OK, 1-8 can be used at most once per number, but there is no rule that you can't use it

1. Hidden conditions.

2. Reasoning. Removing the sum of the four large numbers, 7 and 9, that is, the sum of the remaining four numbers (the numbers in subtraction) is 36-7-9 = 20

3. Further calculations.

a.Two unknowns are introduced to calculate, and the remaining four numbers are x, x+1, y, y+2, referring to two subtractions.

b.The sum of the four numbers is 20, which is (x) + (x + 1) + (y) + (y + 2) = 20

Refer to Hidden Conditions.

That is, 2x 2y=17 to draw conclusions.

IV. Conclusions. Two even numbers and impossible is an odd number, so there is no answer to this question, and the teacher who came up with this question is simply playing all kinds of princes, asking you to help your children do their homework until they doubt life, over.

A: Your question is wrong! There are only eight numbers with 9 parentheses.

（）-=1

Add the four formulas, and the left side of the equation is 12345678 each number is used only once, and it must be an even number.

The right side of the equation = 19 and is an odd number.

You can't fill in the formula that meets the criteria.

There is no solution, all additions or subtractions are even, and the problem is odd, unless 6 is used as 9.

Without solution, the sum of 1+2+3+4+5+6+7+8=36 is: 9+7=16

Therefore, the sum of the four numbers in the formula is: 36-16=20 and the difference between the two numbers in the formula is 1, that is, the sum of the two numbers in the formula is odd, the difference between the two numbers in the formula is 2, that is, the sum of the two numbers in the formula is even, and it can be seen that the sum of the four numbers in the formula is odd, and the contradiction with the previous analysis is 20, so there is no solution to this problem.

The sum of all numbers:

1+2+3+4+5+6+7+8=9x4=36The sum of all kinds:

There are two numbers subtracted, and let their sum be x

Without adding these two numbers, the sum is 36-x

Also subtract these two numbers, the sum = 36-2x

36-2x=19

2x=17x=, not an integer, no solution.

There is no solution to this question.

Since ()+=7 is least likely: 1+6, 2+5, 3+4

1) 1 + 6 = 7, () = 9 There are only 2 possibilities 2 + 7 and 4 + 5

2+7=9, the remaining 3,4,5,8 cannot satisfy ()-=1 and ()-=2 at the same time

4+5=9, the remaining 2, 3, 7, and 8 cannot satisfy ()-=1 and ()-=2 at the same time

2) 2 + 5 = 7, () = 9 There are only 2 possible 1 + 8 and 3 + 6

1+8=9, the remaining 3,4,6,7 cannot satisfy ()-=1 and ()-=2 at the same time

3+6=9, the remaining 1, 4, 7, and 8 cannot satisfy ()-=1 and ()-=2 at the same time

3) 3 + 4 = 7, () = 9 There are only 2 possible 1 + 8 and 2 + 7

1+8=9, the remaining 2,5,6,7 cannot satisfy both ()-=1 and ()-=2

2+7=9, the remaining 1,5,6,8 cannot satisfy both ()-=1 and ()-=2

To sum up: there is no solution to this problem.

12345678 a number can only be used once, on the surface, ()=1, ()=9, ()=7, three groups of one odd and one even, and one odd and one even, it is impossible to get () =2, so this question is not valid. However, it is not forbidden to use functions, so there are many solutions, such as: (8) (7)=1, (3) (6)=9, (4) (ln1)=2, (2) (5)=7.

()-=1 ①

There is no solution, and the proof is as follows:

The sum of the equation is: 9+7=16

Therefore, the sum of the four numbers in the formula is: 36-16=20 and the difference between the two numbers in the formula is 1, that is, the sum of the two numbers in the formula is odd, the difference between the two numbers in the formula is 2, that is, the sum of the two numbers in the formula is even, and it can be seen that the sum of the four numbers in the formula is odd, and the contradiction with the previous analysis is 20, so there is no solution to this problem.

It's a brain teaser, just fill in the 6 as a 9.

1. The result of adding or subtracting one odd and one even is an odd number, so the third question is 3 odd and 3 even, and 2. Two odd or two even are subtracted from the alliance to be even.

So the third title is 2 odd or 2 even.

To sum up: these 8 numbers should be 3 odd and 5 even or 5 odd and 3 even, which contradicts the 4 odd and 4 even in the question, so the original question is not valid.

Odd + Even = Odd.

Odd + Even = Odd.

Even - Odd = Odd.

Odd - Odd = Even.

Even - Even = Even.

It follows that only the addition and subtraction of odd and even numbers can give odd numbers, and the subtraction of two odd numbers or two even numbers can give even numbers.

The result of 4 equations is 3 odd numbers and 1 even number, that is, 5 odd numbers, 3 even numbers or 3 odd numbers 5 even numbers, and 1 to 8 are 4 odd numbers and 4 even numbers, so there is no solution to this problem.

There is no solution to this question.

The three equations equal to , require that each of the two numbers must be an odd number and an even number, so that there is 1 odd number and 1 even number left.

However, if the result is equal to 2, both numbers are odd or even, and the above conditions cannot be satisfied.

The brain teaser solution turns 6 upside down into 9,8) + (1) = 9,2) + (5) = 7,4) - (3) = 1,9) - (7) = 2, and this 9 is written backwards by 6.

Whoever said that this problem is unsolvable, I have already solved it.

Since ()+=7 is least likely: 1+6, 2+5, 3+4

1) 1 + 6 = 7, () = 9 There are only 2 possibilities 2 + 7 and 4 + 5

2+7=9, the remaining 3,4,5,8 cannot satisfy ()-=1 and ()-=2 at the same time

4+5=9, the remaining 2, 3, 7, and 8 cannot satisfy ()-=1 and ()-=2 at the same time

2) 2 + 5 = 7, () = 9 There are only 2 possible 1 + 8 and 3 + 6

1+8=9, the remaining 3,4,6,7 cannot satisfy ()-=1 and ()-=2 at the same time

3+6=9, the remaining 1, 4, 7, and 8 cannot satisfy ()-=1 and ()-=2 at the same time

3) 3 + 4 = 7, () = 9 There are only 2 possible 1 + 8 and 2 + 7

1+8=9, the remaining 2,5,6,7 cannot satisfy both ()-=1 and ()-=2

2+7=9, the remaining 1,5,6,8 cannot satisfy both ()-=1 and ()-=2

To sum up: there is no solution to this problem.

List all the conditions.

Judge in order of (4), (2), (3), and (1).

If 1+6=7, then 2+7=4+5=9

If 2+7=9, then 5-3=2, then (1) is not true.

If 4+5=9, then (3) is not true.

If 2+5=7, then 1+8=3+6=9

If 1+8=9, then 6-4=2, then (1) is not true.

If 3+6=9, then (3) is not true.

If 3+4=7, then 1+8=2+7=9

If 1+8=9, then 7-5=2, then (1) is not true.

If 2+7=9, then 8-6=2, then (1) is not true.

So there is no solution, unless 6 is poured into 9

12345678 four odd numbers, four even numbers()+=9 must be an odd number, an even number ( =7 This question must also be a singular number, an even number ( )=2 must be both odd or even ( =1. It is necessary to have a single double, and it is comprehensively known that the four formulas need to meet the needs of three singles and five pairs or three doubles and five singles at the same time, and 1-8 four singles and four doubles, the conditions are not met, so there is no solution.

Solution: Hypothesis.

a-b=1...1)

c+d=9...2)

e-f=2...3)

g+h=7...4)

(1)+(2)+(3)+(4) (a+c+d+e+g+h)-(b+f)=19 .5)

and it is known that a+b+c+d+e+f+g+h=1+2+3+4+5+6+7+8=36 .6)

From (6)-(5), we get 2(b+f)=36-19=17, i.e., b+f= The result does not meet the assumption: b and f are integers.

So there is no solution to this problem.

The conditions are contradictory, there is no solution to this problem It would be nice if there were 9.

There is no solution to this question.

There can be no answer.