Fun Elementary School Math Problem 4, Fun Primary School Math Problem

Known: 1 3 = infinite loop).

Because: infinite loop) + infinite loop) + infinite loop) = infinite loop) and because: 1 3 + 1 3 + 1 3 = 1 Conclusion: 1 3 infinite loop)? Contradicting the known?

Who's going to explain what's wrong?

Infinite loop) can be regarded as 1, according to the limit lim n can indeed draw such a conclusion, but infinite loop) = 1 3 times 3 to draw the conclusion is 1 or infinite loop) if = infinite loop) how to express it in mathematical expression. Please give a detailed reasoning process. For example, if it is 1 6, his 3 times = but 1 6 = infinite loop) his 3 times, the last digit is 8, which is the result is an infinite 9) 9998, with this ending number 8, he is not an infinite 9, he becomes a finite set.

Is it so infinite 9) 9998???

There is an airplane that takes one hour to fly from A to B, and it takes two and a half hours to fly from B to A, how many hours is the difference between two times?

What do you mean? I think it's interesting, maybe you don't

Question 1 If the sum of a four-digit number and a three-digit number is 1999, and the four-digit number and three-digit number are made up of 7 different numbers. So, how many such four-digit numbers can there be at most?

Question 2 There are four cards with one number written on each front. The first sheet has 0 and 1 written on it, and the other three have 2 and 3, 4 and 5, 7 and 8 written on it. Now take out any three of these cards and put them in a row, so how many different three-digit numbers can be formed?

b＋e＝9，（e≠0），c＋f＝9，d＋g＝9。

2.(7 6 4) 168 pcs.

Fun math problem A walks 12 kilometers per hour and B travels 8 kilometers per hour. On a certain day, A went from the East Village to the West Village, which is the fourth question of the third major question in the final paper of the 15th "Spring Festival Cup" Mathematics Competition for primary school students in Beijing.

The question is not right, it should be dead each time carrying 3 people, because the police and the prisoner can't leave, the father and son can't leave, the mother and the daughter can't leave, so the police and the prisoner, the father and the son, the mother and the daughter must be together, but only the father, mother and the police can hold the boat. So the boat can't come back when it reaches the other side, unless the two of them come back again.

Police and prisoners,Fathers and daughters, mothers and sons.

There is a problem with the topic.,The daughter and mother are three people.,The father and son are also three people.,The boat can't carry it.。。

Police and prisoners,Dad and son, mom and daughter.

Is there only one small boat on the river? Do you carry 2 people at a time, including the punry?