1. If A wants the last piece, he will leave three pieces for B in the end, so it is the ultimate goal of A to leave three pieces for B. At first, A takes two pieces, leaving 5 1, and then if B takes 1, A takes two pieces; B takes 2, A takes 1 ... and so on, each cycle will be reduced by three, and finally ... After A takes 17 times, there are three times left, B takes 1, and A has two times; Two for B, one for A .. Jiabisheng.

2. Of course B can win, 1994. A can only take odd blocks the first time, and will not take them away. After A takes an odd number, the remaining numbers must be odd, so that B can take them all at once.

3. Same as the first question. A reports 5 first, and then B reports 7 no matter how many times-that number. When A reported the 286th number, A won.

4.

5. If you don't get the last one, you actually want to get the penultimate one, so the original question is equivalent to: If there are 999 matches, everyone takes 1-7 in turn and asks how to win. Same as the previous question: the first one wins, the first one wins, and then the number of others wins, so you can subtract the number of heels from 8, and after winning 125 times, you win.

6.

7. Leave a small square for the other party, that is, leave a 2*2 square for the other party (the other party has only one cut, and then you can give the other party a small square). Similarly, leave a 3*3 square for each other. So, the person who cuts the knife first wins. At the beginning, cut the 7*3 square into 4*3 and 3*3 (take 4*3 and leave 3*3), and the other side will leave 2*2 after cutting the knife (even directly 1* 1), and then it will be very simple.

8.

9.

10.a Take a pile first and leave only one pile. If b takes this pile away, it's okay to take another pile until there is only one pile left. If b only takes the other pile, it can be said that b can't win anyway. If B takes a part of the other pile and doesn't take all of it, A takes all of the other pile.

There's no time to do it in the back