03:26

what is the area of a star ?

06:03

how to find the diameters of the Moon and the Sun 2,300 years ago! (Aristarchus)

03:59

area of a regular hexagon? transform it into a rectangle!

04:18

geometric proof of the quadratic formula (graphing equations)

03:49

tan 36 degrees, how to find the value. (trigonometric function)

04:01

A Hypercube: What Shapes Enclose It, and How Many? how many vertices?

04:32

correct solution to ax+b=0. 9 out of 10 don't know. (+graphing linear equations)

01:14

how to find the remainder when divided by 9. why???

04:36

proof of area formula of a regular pentagon, using the diagonal.

03:14

what is the area of the shaded region ?

04:07

what if a negative times a negative equals a negative ?

02:33

what is the diameter of small semicircle?

03:30

what is the area of the colored part?

03:40

this is not a square, but a circle, here!

04:02

How to create magic squares of Olympic Rings with numbers,1 to 9.

02:38

how to find the area of Mercedes-Benz logo

02:15

how to find the radius of a circle !

01:42

How to find the area of a trapezoid in seconds.

04:12

principle of checking multiplication & how to check!

02:22

how to find the total area of the circles in a second!

04:49

how negative number was invented in BC? by equations?

04:09

if A⊈A, what happens to empty set? (if any set is not a subset of itself)

04:09

number line, who invented? why and when? --math history--

04:19

Associative property made Gauss a great mathematician!

03:40

∅∩∅=?, ∅-∅=? empty set operation, how to solve?

03:45

why Zeno's paradox was presented? due to Pythagoras? --proof by contradiction--

04:40

who invented zero? why in Mesopotamia? -- 0 history --

03:42

Empty set, why invented? - birth history of empty set -

04:12

Commutative property made Gauss a great mathematician!

05:00

guinness record numbers related to Christmas!

04:16

numbers & statistics about Christmas, globally! -'white Xmas' to '0 Xmas'-

04:38

why 7 members of BTS & 7 Dwarfs in Snow-White ? [math of symbol]

04:00

Pythagorean Theorem is in your smartphone! [resolution & ppi]

04:57

How Mary calculated 57×135 so quickly? -Trachtenberg math, movie 'Gifted'-

04:30

why 1 is not a prime number? [math history of definition]

05:04

why 1(one) was a prime number? [math history of definition]

03:40

Find the number 7 in Snow-white & 7 Dwarfs! [symbol of 7]

01:59

2, 4, 6, 8, (?) / 10 is foolish! Any number is genius! [secret of sequence rule]

04:16

Math in Socratic method(ignorance) -Pythagorean theorem and √2-

04:17

Gauss constructed Pythagorean Theorem in Siberia to conatct Aliens ? [application & history]

03:22

Negative mass, already discovered! mathematical definition & negative number.

03:58

Math in platform 9 & 3/4 of Harry Potter. why 9 and 3/4? [symbol of 9]