Current location - Training Enrollment Network - Mathematics courses - A math problem
A math problem
Let this number be ABCD.

Then the value of this number is equal to: (1000a+100b+10c+d) Suppose the large number is CADB.

Then the value of this number is equal to: (1000c+100a+10d+b), subdivided into BDAC.

Then the value of this number is equal to: (1000b+100d+10a+c), so

Large number-exact number = original number (1000c+10a+10d+b)-(100mb+10d+/kloc) = (60) D = 0.................( 1) Number size: C > A>D>b Try the equation with different numbers (1): 989c = 910a+1099b+91d Let c =

LHS = 890 1, because the unit number is 1.

So try to B=0.

D= 1 or B= 1.

D=2 and so on. In short, let the unit number of (1099B+9 1D) be 1. Finally, if a is an integer and satisfies C > A>D>b, it is true. Otherwise, try C=8 again.

C=7 ... After more than one round of routine attempts, C = 3...C = 7.

LHS=6923, because the unit number is 3.

So try to B=0.

D=3 or B= 1

When B= 1, D=4, and so on.

When D=4

6923 = 910a+1099 (1)+91(4) 6923 = 910a+1463a = 6 so C=7.

A=6

D=4

B= 1 (C > A >D>b) So this number is 6 174.

(large number =764 1

Fine number = 1467

Large number-precise number = 6174) 2007-05-12 23: 22: 56 Supplement: There may be other answers ... because the number of people may be BACD.

Maybe CBAD, ........... and so on.

Reference: yourself (if there is a better way, please tell me)

Du 5 knows you

Incomplete guesses are also the best.

Good method, mine is close. Note that its requirement is to subtract the maximum four digits from the minimum four digits, so it is more convenient to set the maximum value directly when setting, because the maximum value is ABCD and the minimum value must be DCBA. The difference is: (1000a+100b+10c+d)-(100d+100b+a) = 999a+999a. Let the four digits divisible by 9 be pqrs = 9k1000p+100q+10r+s = 999p+99q+9r+s+p+q+r+s = 9k, so p+q+r. +9 R+S)) can definitely divide 9 A+B+C+D = 9 from 0000-9999, just take out the multiple of 9 (111,which is more than the original 10000. Get the answer 0000-0000 = 0000 7641-kloc-0/467 = 6174 2007-05-1318: 02: 40 Supplement: add a little. 2007-05-2413: 43:10 Supplement: Your answer is better than mine. :'(

Reference: trying all possibilities, also known as exhaustive method, is one of the methods. It's only a thousand numbers, and the computer is so fast.