⚖️ 天平找次品Fake Coin Balance
在线天平找次品：一堆外观相同的硬币里混着一枚次品，只能用一架没有砝码的天平比较两边轻重，在规定次数内把它找出来。从 3 枚称 1 次、9 枚称 2 次、27 枚称 3 次，到最难的“12 枚硬币称 3 次，次品不知是轻是重”，共 5 关。次品不是事先定好的，靠猜碰不中，必须用对方法。Fake Coin Balance online: one coin in the pile is fake, and all you have is a balance scale with no weights. Find it within a fixed number of weighings — from 3 coins in one weighing, 9 in two and 27 in three, up to the famous 12 coins in three weighings where you don't know if the fake is heavier or lighter. Five levels. The fake is never fixed in advance, so lucky guesses don't work — only a sound plan does.
点硬币依次放到左盘、右盘、拿下来；两边放好后按“称一称”。想好了就按“指认次品”再点那枚硬币。Tap a coin to put it on the left pan, the right pan, or take it off; then Weigh. When you are sure, press Pick the fake and tap the coin.
玩法说明与常见问题How to play & FAQ
「天平找次品」怎么玩？How do I play Fake Coin Balance?
每关告诉你硬币数量、次品是偏轻还是不知轻重，以及最多能称几次。点硬币把它放到天平左盘或右盘，两边数量相同才有意义，按“称一称”看结果：平衡、左边重或右边重。称完后按“指认次品”，再点你认为的那一枚（不知轻重的关卡还要选“偏轻”或“偏重”）。只有称量结果已经能唯一确定次品时才算找对——如果还剩几种可能，就算你点中了也只是运气，不算过关。Each level tells you how many coins there are, whether the fake is lighter or could be either, and how many weighings you get. Tap coins onto the left or right pan (equal numbers on each side make sense) and press Weigh: balanced, left heavier or right heavier. Then press Pick the fake and tap your answer (on the unknown level also choose lighter or heavier). You only win if your weighings have pinned the fake down; if several coins are still possible, a correct guess is just luck and does not count.
为什么 9 枚只要称 2 次？Why do 9 coins need only two weighings?
把硬币分成三组，每组 3 枚，先比两组：哪边轻次品就在哪组，平衡就在第三组。再从那 3 枚里拿两枚比一次就知道了。每称一次可能性就缩小到三分之一。Split them into three groups of three and weigh two groups: the lighter side holds the fake, or the third group if balanced. Then weigh two of those three coins. Each weighing cuts the possibilities to a third.
“次品不是事先定好的”是什么意思？What does “the fake is never fixed in advance” mean?
每次称完，程序都会挑一个仍然符合所有称量结果、对你最不利的答案。所以只要还剩不止一种可能，你点哪一枚都可能是错的，只有用对了方法才能必胜。After each weighing the program keeps the answer that is still consistent with every result and worst for you. As long as more than one possibility remains, any pick can be wrong — only a correct plan guarantees a win.
「天平找次品」免费吗？需要下载吗？Is Fake Coin Balance free? Do I need to download anything?
完全免费，无需注册、下载或安装，打开网页就能玩，手机、平板和电脑都支持；游戏完全在你的浏览器本地运行，不会上传任何数据。It is completely free with no sign-up, download or install — just open the page on a phone, tablet or computer. The game runs entirely in your browser and nothing is uploaded.