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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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4.2 ★★★★★
Based on 21 reviews
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Product Reviews
★★★★★ 5
I give a 10,
Color: Black, Item Package Quantity: 1
I love it easy to symbol
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Reviewed in the United States on March 23, 2026
★★★★★ 1
End table
Color: Black, Item Package Quantity: 2
Size was not what I expected
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Reviewed in the United States on May 16, 2026
★★★★★ 5
Solid Floating Shelves 🛠️🏠
Color: Black, Number Of Shelves: 4, Size: 15.7in
I have installed four sets of the black floating shelves in my office. They are made of high quality materials, featuring a sophisticated black woodgrain finish with a natural texture. Supposedly, each unit can handle up to 22 pounds, though I would not recommend testing that limit with your vintage bowling ball collection if you value your flooring. They are awesome.
The value is good for a set of two. Each shelf measures 22x7x1 (56x17x3 cm) inches, providing a decent amount of storage for books or decor. The installation was straightforward since the hardware for multiple wall types was included. They work well in the kitchen for spices or in the bedroom for personal belongings.
One tip for a secure fit: use a level during installation and make sure the bracket is flush against the wall before sliding the shelf on, or your photos might look like they are sliding off a mountain 📐
These shelves offer a clean, modern look and stay stable once mounted correctly. They are a practical choice for adding functional display space to any room 🖼️
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Reviewed in the United States on May 4, 2026
★★★★★ 5
Good looking shelves and easy install - skip the included drywall anchors
Color: Black, Number Of Shelves: 2, Size: 22in
I installed these shelves in a bedroom to get things off my dresser and some decor. Once mounted they look really nice. The black finish looks clean and modern and they blend in well with the room.
Installation was pretty straightforward. The metal bracket mounts to the wall first and then the shelf slides over the bracket. As long as you take your time lining things up it’s a simple project.
One thing I strongly recommend is not using the white plastic self-drilling drywall anchors that come with the kit. I’ve used that style before on other projects and they tend to strip out easily and leave larger holes in drywall. I used better anchors instead and the shelves mounted much more securely.
The rest of the hardware worked fine and once installed the shelves feel solid and hold items well.
Pros
- Clean modern look
- Easy installation
- Feels solid once mounted
- Good size for books or decor
Cons
- The small level included isn’t very accurate — use your own level
- One of the metal brackets was slightly bent out of the box but straightened out easily
Helpful tip:
Use your own level and better drywall anchors if you have them. It makes installation easier and the shelves will mount much more securely.
Final thoughts:
For the price these are nice looking floating shelves that install easily and work well for light storage and decor.
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Reviewed in the United States on March 13, 2026
★★★★★ 5
Cheap, and effective!
Color: Black, Number Of Shelves: 4, Size: 15.7in
Looks good, works great, low cost. I'll be purchasing more in the future.
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Reviewed in the United States on May 12, 2026