Current location - Training Enrollment Network - Mathematics courses - Mathematics interesting answering questions
Mathematics interesting answering questions
1 and a * * * can form 15 natural numbers.

Among them, one digit is 5, 7 and 9.

These two figures are 57, 59, 75, 79, 95 and 97.

These three numbers are 579, 597, 759, 795, 957 and 975.

2. A * * * can form 10 natural numbers.

Among them: a number has 4 and 6.

These two numbers are 40, 46, 60 and 64.

These three numbers are 406, 460, 640 and 604.

3. If there are x chickens, there are 12-X rabbits;

Because a chicken has two legs and a rabbit has four.

Column 2X+4( 12-X)=30.

Found that X=9

12-9=3

The Zhang family has 9 chickens and 3 rabbits.