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Ann doesn't like math.
1. I wonder if the diagram is correct. Have you learned the equation? I think you can see it clearly.

2. The number should be (2.88-2.54)× 10=3.4 and the correct answer should be 5.94.

3. Method 1: Countdown

? Before the 10 pass: (2- 1)×2=2.

? Before the ninth pass: (2- 1)×2=2.

......

? So what? There were two at first.

Method ⅱ, equation method, too much trouble, suggested usage ⅰ.

4. (Now the questions of primary school students are wonderful and a bit tricky-? -)

Perform the following analysis:

No matter what you think,

If it's time for the other party to take it,

With two coins left, he took 1 and I lost.

When there were three coins left, he took two and I lost.

When there were five coins left, he took four and I lost.

But when there are four coins left, no matter how he takes them, he can't win.

That's him taking 1, and I'll take 2.

He takes two and I take 1.

He lost when he got four!

So the secret of winning is to find a way to leave four coins for each other!

Suppose I take it first,

If I take 1 first and the opponent takes 2, I can't leave him four coins at this time, and then I will lose anyway.

If I take two coins first and the other person takes four, then he will leave me four coins, and then no matter how I take them, I will lose.

If I take four coins first and the other person takes two, then he will leave me four coins, and then no matter how I take them, I will lose.

So the person who takes it first will definitely lose!

So the way to win is:

Take the coin later!

A. If the opponent takes 1, I will take 2.

A. After that, if the opponent takes 1 piece, I will take 2 pieces and leave 4 coins for him, so I will win in the end.

B. After that, if my opponent takes 2 pieces, I will take 1 piece and leave him 4 coins, so I will win in the end.

C. After that, if my opponent takes 4 pieces, I will take 2 pieces and leave him the last 1 coin, so that I can finally win.

B. If my opponent takes 2 pieces, I will take 4 pieces directly and leave him 4 coins, so I will win in the end.

C. If my opponent takes four, I will take two directly and leave him four coins, so I will win in the end.

5.-? Poor student.

I want to know whether those two diagonal lines are parallel, otherwise I can't do it, I can only work out the range of values.

Well, suppose they are parallel.

The red pen is the auxiliary line I made.

Sister has been doing it for a long time, and there may be a calculation error (unlikely). I hope you can think more about it in the future and try to do it independently, although it's difficult- -。

I hope this helps.