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Merry Christmas and Happy New Year





New Year Puzzle: In a magic square, the sum of numbers on each row, each column, and each diagonal is the same. Fill in the numbers in the following squares to make them become magic squares.



Which is smaller? which is larger?



Today let us look at the following two tricky questions:

Question 1: Among these two numbers 4444 x 55555 and 5555 x 44444, which one is smaller? which one is larger?


Question 2: How about  5000 x 5000 and 4999 x 5001, which one is smaller? which one is larger?

Vianney's awesome square!

The reasons that this square is so awesomistic are:
  • each entry is a square number: $$1=1^2, \quad25=5^2, \quad 49=7^2$$
  • the sum of numbers on each row, each column, and each diagonal is the same.



Radian


On this $\pi$ day occasion, we will learn about the concept of radian.


Pythagorean Identity


This year we will start a blog series about mathematical identities. Let us begin today with the Pythagorean Identity $$ a^2 + b^2 = c^2 $$

Fibonacci numbers and continued fractions


Fibonacci is probably the most well known sequence in mathematics. Today, we will see how Fibonacci numbers can be used to construct beautiful patterns called continued fractions.

Divide a line segment by compass


Using compass and straightedge, we can construct the midpoint of a line segment, and we can easily divide a line segment into, say three equal parts. The question is, is it possible to do these constructions with just the compass.

The answer is "yes"! Indeed, it is possible to construct the midpoint of a line segment, and it is possible divide a line segment into a number of equal parts by using the compass alone. How amazing is that?! Today, we will look at these constructions!

Construction by compass alone


Normally in geometric construction problems, we use straightedge and compass. Today, we will look at an unusual type of construction problems where we are only allowed to use compass.