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數學男孩圓周率之旅 (臺灣大學名譽教授 張鎮華): 3. 143. 1416 3. 1415926 201931. 4 108
作者: 張鎮華
圓是自然界與生活上常見的美妙形狀，它是神賜給人類的寶貴禮物，人自古以來就致力於瞭解其性質。要瞭解圓，就要瞭解圓周率，這個反應它的一個重要常數，小學時老師告訴我們圓周率是3.14，長大一點以後精確度提高到3.1416，到後來就用符號記為π。
整本書以數學男孩吉拉一生的經歷，串起古今圓周率計算的工作，並適度介紹與圓周率相關的數學。故事起自吉拉和女兒們討論圓周率，轉而回憶吉拉小時的求學經驗。
吉拉小學國語老師挑戰他們計算面積，接到初中學習幾何知識配合根號求值解決問題，輾轉到古代人對於圓周率的計算，集其大成者是南北朝數學家祖沖之，他求得的3.1415926是之後一千年內最精確的值。
吉拉四姊計算平方數的挑戰，及他高中時對於完全數的迷戀，指向數學上的計算很容易到達人力的極限。吉拉學習電腦的故事逐漸展現，數學知識加上電腦的威力，讓一些人力不能及的計算，完成到前所未有的境界。現代人對於圓周率的計算就是這個浪潮下的一個小浪花，其中2019年日籍女工程師岩尾算到小數點後31.4兆位數是一個旅程碑。
整本書以數學男孩吉拉一生的經歷，串起古今圓周率計算的工作，並適度介紹與圓周率相關的數學。故事起自吉拉和女兒們討論圓周率，轉而回憶吉拉小時的求學經驗。
吉拉小學國語老師挑戰他們計算面積，接到初中學習幾何知識配合根號求值解決問題，輾轉到古代人對於圓周率的計算，集其大成者是南北朝數學家祖沖之，他求得的3.1415926是之後一千年內最精確的值。
吉拉四姊計算平方數的挑戰，及他高中時對於完全數的迷戀，指向數學上的計算很容易到達人力的極限。吉拉學習電腦的故事逐漸展現，數學知識加上電腦的威力，讓一些人力不能及的計算，完成到前所未有的境界。現代人對於圓周率的計算就是這個浪潮下的一個小浪花，其中2019年日籍女工程師岩尾算到小數點後31.4兆位數是一個旅程碑。
作者
張鎮華
退休後現為臺灣大學名譽教授。年輕時取得美國康乃爾大學運籌學博士學位，回臺灣後先後在中央大學、交通大學、臺灣大學任教。一生致力於離算數學及組合最優化研究，特別是圖論及其演算法，發表過專業論文兩百多篇及專書三冊。曾參與108數學課程綱要研修，撰寫相關介紹文章數十篇。
張鎮華
退休後現為臺灣大學名譽教授。年輕時取得美國康乃爾大學運籌學博士學位，回臺灣後先後在中央大學、交通大學、臺灣大學任教。一生致力於離算數學及組合最優化研究，特別是圖論及其演算法，發表過專業論文兩百多篇及專書三冊。曾參與108數學課程綱要研修，撰寫相關介紹文章數十篇。
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4.1 ★★★★★
Based on 26 reviews
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Product Reviews
★★★★★ 5
As durable as expected.
Size: Large, Color: Femur Bone, Size: Large, Color: Femur Bone
My dog loves it—more than any other bone she’s ever had. It’s not quite as durable as regular nylabone, but we expected that. This photo was taken after around 2 hours of super aggressive chewing by a very big German shepherd. It has no discernible smell, but obviously it has a flavor because she doesn’t want to put it down even for trips outside. It’s soft enough that it doesn’t cause that “are their teeth breaking?!” sound that a lot of offbrand nylon chews have. The classic femur shape is perfect. It’s the easiest shape for her to hold naturally. All around, perfect dog chew.
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Reviewed in the United States on April 11, 2026
★★★★★ 4
Heavy duty chewing, not heavy duty dropping
Size: X-Large, Color: Textured Ring
My super chewer loved this toy, great shape, provided long lasting entertainment. However, when he dropped it from his mouth onto our epoxy flooring (not a far drop as he’s only 50lbs) one chunk broke clean off at the 2 smaller joints. Although we kept the larger piece for a while, a similar drop a week later broke it again. Considering this is fairly inexpensive, I wasn’t expecting it to be indestructible. It’s just strange how it broke. Will probably buy again to test one more time.
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Reviewed in the United States on March 9, 2026
★★★★★ 5
My dog loves these things
Size: Large, Color: Femur Bone
My dog loves these things. They don't smell at all. It was a great price. It's big enough for my Frenchie. It's pretty durable but he is able to gnaw it rough so I do have to replace them periodically.
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Reviewed in the United States on March 24, 2026
★★★★★ 5
Doggo Approved
Size: X-Large, Color: Textured Ring, Size: X-Large, Color: Textured Ring
About as indestructible as it gets. It's just very hard molded material. I always make sure to wash the dog toys before letting them play, who knows where they come from. Picture is after hours/days of the built playing with it
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Reviewed in the United States on May 26, 2026
★★★★★ 5
Old Faithful
Size: Large, Color: Wishbone, Size: Large, Color: Wishbone
AmStaf/Lab loves this product. I am still concerned about him ingesting the sharp little pieces he gnaws off, but he seems OK after three months of using these. Tried the Nylabone natural/wild products but they are not usable as a "chew" and disappear within minutes, nay seconds!
-So here I am back to the "strong chew" wishbone product which makes my dog happy and keeps him busy not eating my shoes. (Be warned though, these are worse than Legos if accidentally stepped on!)
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Reviewed in the United States on April 13, 2026