Tag Archives: learn

Degrees and angles | 角度

Today in the fourth grade weekend lesson we learned about angles📐 and degrees. We explained what degrees was first🥇 because angles are classified using degrees📏. Degrees were discovered by Egyptians. They invented the degree symbol ° and also came up with the 360° circle⚪.  There is an interesting history of how they connect the movement of the Sun with time.   They first divided a year into 360 days, noting that the Sun moved in a circle. Around 1500 BC Egyptians divided 24 hours⏳, though the hours varied with the seasons originally. Then the Greek astronomers made the hours equal. About 300 to 100 BC the Babylonians subdivided the hour into base-60 factions: 60 minutes an hour and 60 seconds in a minute.

We use degrees to measure angles. An angle is a figure formed by two rays🛴 called sides of the angle. In geometry there are three types of angles: an acute angle between 0 and 90 degrees, right angle a 90 degree angle, and an obtuse angle between 90 and 180 degrees. In 1936 a clay tablet was found buried at Shush (Khuzestan region of Iran🌏) some 350km from the ancient city of Babylon on which was inscribed a script that was only translated as late as 1950. The text provided confirmation that the Babylonians measured angles using the figure of 360 to form a circle. The Babylonians knew that the perimeter of a hexagon was exactly equal to six times the radius of a circumscribed circle. This is why they chose to divide a circle in 360 parts⚪. If we did not discover degrees or angles we would not be able to build anything properly🧱. So if we tried building a house without degrees or angles the house would collapse🏚.

We will talk about triangles next time.

Welcome to our New Google Classroom!!😃

Hello everybody!😃 Welcome back to Magic Math Mandarin.  Since we are staying home because of covid-19, we brought our classes to google classroom so our students can keep on learning even during this pandemic👩‍🏫. Now we can all communicate with each other online💻. In this classroom we will be learning Chinese🈷, math➗, and programming👩‍💻. Our teachers will put new assignments everyday about each topic.  If you would also like to join our wonderful classrooms then here is the class code mtxl6j4

Remember to stay home and don’t get sick!😷 Please join our classroom today!👍💖


Virtue of memorization in learning math

The biggest ones in word cloud associated with memorization are probably “boring” and “meaningless”.   People never hesitate to trash memorization and praise free creative learning.   To me, however, memorization means discipline and foundation building for creative or any other learning, dumb or smart. Without the foundation and/or frame built by memorization, there is no ground for free creative thinking.

In a math class with Professor Patrick Gallagher at Columbia University, one of our first quizzes was to write down the exact definition of “partition.” I went to the professor and protested, “Why do we have to write it out word by word; can’t we just get it close?” Professor Gallagher smiled and said nothing.  He might have been thinking, “She really does not know what she is talking about.”

In order to pass the quiz, I memorized the definition of “partition” word by word. I am still enjoying the many benefits of it: the meaning of MECE (“mutually exclusive, collectively exhaustive”) and the method of problem solving.   I apply this method of problem solving in my data analysis frequently.

“Limit”, “continuous” are among some other definitions that I memorized.    Just reading the descriptions won’t give you anything. Reading the definitions again and again, until I memorized it by default, helped me develop understanding and appreciation of the art of mathematics. The understanding of limit is essential in calculus; it was as beautiful as the best poetry “to hold infinite in the palm of your hand” (Tagore).

No pain, no gain.   Where do we think we are going with only fun and no pain?   The true reward at the mountain top does not come free with easy roaming.


Two Chinese schools & one great library

library Chinese books
Chinese books at Livingston Library

According to Wikipedia, Livingston, NJ, has about 30,000 people and about 20% Asian and 50% Jewish.

Victoria reading at Livingston Library
Victoria reading at Livingston Library

It has two Chinese schools within one zip code and minutes from each other: Livingston Chinese School李文斯頓中文學校and Livingston Huaxia Chinese School 李文斯顿华夏中文学校.   During 2007–2008 budget year, Livingston allocated 60% of local property tax to  the Livingston Public Schools. 

Pulbic Library at Livingston
Elizabeth & Victoria at Livingston Library

Additionally, a separate budget of 7% of all municipal services went toward the operation of its public library. According to library statistics collected by Institute of Museum and Library Services, Livingston Public Library was ranked 22 out of 232 municipal libraries in New Jersey based on total circulation in 2006.

Livingston Chinese School (李文斯頓中文學校) was founded in 1983 and opens on Sundays from 1:30 to 4:10, 是唯一在北澤西提供以傳統正體字為主的中文注音符號,漢語拼音, 及粵語三種教學的中文學校.    Livingston Huaxia Chinese School (李文斯顿华夏中文学校) was founded in 2002 and opens on Saturdays (每星期六上午9:00到下午2:05).

From the numbers, it is apparent that the town places strong emphasis on education and culture.  Add these to low crime rate and vicinity to NYC, this is surely a great place to live.

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