Murderous Maths Tricks

[dedly13]

this guy is very good irl, iv seen him

[131T3M3]

In the last trick, the two 5x8 triangles that appear to make up the large rectangle are, in fact, not triangles. If you take out the 3 x 5 rectangle in the middle of the large triangle (the top of this rectangle is that line that divides the two triangles), the remaining two triangles are 2 x 5 and 3 x 8. Since these 2 right triangles are not similar, the big triangle was actually not a real right triangle. So, in fact, there is a small gap between where the marker is that makes up the 65th sq

[ZHAROVAN]

the second figure is ne a perfect rectangle , the width is not constant a long the length

[PenileFracture]

Press 2 for a surprise

[Fallschirmjaeger963]

Last trick: surface is presented by a 2nd degree function. it's somewhere in my math book..another example: you have a wire of 13 m. you want to connect your house and garage with that wire, and make a rectangle. so the question is, how long should the length and broath be so that the surface is maximal? the length = x broath = y x + y = 13 y = 13 - x S(urface) = y . x S = (13-x) . x = -x² + 13x = -1x² + 13x -1 < 0 TOP of the graph: -b/2a = 6,5 etc.

[TheMeGenius]

For cool math tricks to calculate faster visit my channel :)

[therealkakkamakkara]

Oh why did you do the last one. It's just a dumb visual trick, nothing to do with math.

[jugernotash]

The second trick was good but first was kinda obvious.. 7x11x13 is 1001

Any 3 digit no. multiplied for eg. 256 would be 256256 and so on..

[Fduffle]

do you know what thats called? yes. what is it? its a square. no its not

[Deretythe]

I pressed 1, then 2... It sounded like "On that side it's just gotta die - surprise!"

I have no idea why, but that made me laugh so hard...

[arixria]

guy in the background at 0:47 is probs like WTF........

[Techn0Dtragon]

If you keep on pressing 3 it looks like he's waving a wand o.o and if you keep on pressing 4 it seems like he's saying Osama

[averygrandma]

Keep pressing 2 on the keyboard :

"Surprise"

"Surprise"

"Surprise"

...

"Surprise"

[killsome49]

thumbs down if you tried to do the pentagon thingie but failed

[anticorncob6]

@killsome49 Why thumbs down? You know that if a comment recieves a negative vote then it gets pernametely deleted!

p.s. I couldn't do it and I voted that down

[killsome49]

@anticorncob6 coz im ......mapagkumbaba.yeah.i wanna feel lower than others.i wanna make myself a "pawn" in a chess.but then when i reach the top of my opponents side,i could "revive" something.......

[Zeegoner]

2:04 australians represent

[xsni]

nerdy little laugh

[luckystar861026]

the gradients aren't the same - -

[TheTaylorfull]

the angle between the lines of the two grids are not the same. they are slightly different.

[cooll930]

It's easy :P

the triangles' sharpest angles are approximately 20.56 degrees

the sharpest angles of the other shapes are approximately 68.20 degrees

the sum of those angles is approximately 88.75 degrees, which is NOT 90 degrees.

the third angle is so small, that you won't notice it at first.

I first thought I just sucked at using scissors XD

[mrsonicdash10]

i got one

66x67=

666x667=

6666x6667=

[MrKit2010]

why 65 square? Look agian to picture with 64s. and u can see he has a THICK RED LINE when u reshape that u can get 1 square ^^!

[Thraximunder]

@MrKit2010 its actually because the diagonal lines will make up a differnt area when arranged differently, the explaination is here: h t t p : / / w w w . m i c h a e l b a c h . d e / o t / a n g _ t r i a n g l e P u z z l e / i n d e x . h t m l (without the spaces)

[MrKit2010]

@Thraximunder thx...but i cant fuond this page

[IOUAQT2]

2:04 A five sided thing is called a . . . square LOL

[veryfatal]

Hey everyone I just finished creating a math tricks website for those who need help improving mental math and basic arithmetic skills. Please check it out and let me know what you think of it. My site is mathtipsandtricks . com

[CoolBillyTech]

keep clicking at 3:27 :D

[kindsoohyun1]

cool



[dianabxh]

If you look at the big triangles drawn at the square 8 x 8, it is not a correct drawing. Look at the third row (starting from the base below), the hypotenuse cuts the third row of the squares at the (up)right vertex of the first square, where two squares are left (which is wrong). Look at the similar triangles that are formed, 2/3 = 5/8! In this way, he filled out the gap of .25 (4*.25 = 1 square)

[moonlightguardian]

i could tell right away this wasn't in america just because we definitely don't do math on the street o_o....

[2Cheater2]

It's actually not matching because of that it's an extra suare. Just do it in Photoshop or whatever and zoom in and you will see.

[toomanysam]

surely the extra square is just rounding from the split squares before hand?

[puncheex]

Martin Gardner reprised!! Lay on, Sir!!

[puncheex]

@wubs23: Actually he already knows what 7 x 11 x 13 is; it's 1001. so as long as the number you multiply by is three digits or less, the result will be that number followed by the same number filled to three digits.\

1001 x 26 = 26026.

[camucase]

the extra square come from the red lines guys

[dogonskis]

this is friggin absurd... area doesnt change by itself when you just move it around -.-

[puncheex]

@dogonskis: The trick is that the angles on the triangular pieces and the truncated triangular pieces aren't exactly the same. If you draw the parts very carefully and cut them carefully, when you reassemble them into the second pattern you'll see the long diagonal lines don't quite come together. The area difference spread along that long line is exactly one unit.

[puncheex]

@dogonskis: The trick is that the angles on the triangular pieces and the truncated triangular pieces aren't exactly the same. If you draw the parts very carefully and cut them carefully, when you reassemble them into the second pattern you'll see the long diagonal lines don't quite come together. The difference spread along that long line is a parallelogram of exactly one unit area.

[smorkodbake]

@puncheex what ya say :D

[0000infinity0000]

7 people don't have an extra square.

[mcuriousyellow]

haHAhaHAhaHAhaHA...aaahh!!

[LilReaper1010]

THE EXTRA SQUARE IS A LIE!

[seahawk124]

That last one is due to the fact there is a long thin space running diagonal across the rectangle, which equals to the same area as one square on the paper.

[theboombody]

Notice that 7 times 11 times 13 equals 1001. Take any three digit number (where each digit is between 1 and 9) and you'll find it's pretty easy to multiply it by 1001 in your head.

[ryansdogsadie]

7+9=banana

[HumaninSeoul]

This is annoying as hell. That man should be locked up in an asylum. He adds nothing but discomfort to the lesson.

[gadunka888]

@HumaninSeoul

well he probably knows more math stuff than you.

[lmc6506]

It's not a magic

[verymadrobert]

there's a VERY small gap in the middle of the rectangle

[jdfox1]

The slopes arent equal on the grid. A square...ha ha! :)

[buchanproductions]

i have met him

[BicycleHunter999]

did this guy came to my skool todaii. hes so funyy

[thegoonist]

its a very small angle so most people wont notice the slight difference unless you spot the 2 triangles of different sizes and realise it.

[PegasoltaEclair]

Put that one there = ut'aton'air

[jhelen90]

well.... 7*11*13 = 1001 is just soooo well-known.....

[alewisgb]

extra square = hypotinuse different

[TripleEliteS]

nice i love it i was amazed!!!

#LOL

[RobertBorgersen]

lol

1. 7*11*13 = 1001. Any 3 digit number * 1001 is easy. xyz * 1001 = xyzxyz

3. extra square came from the fact that it was not a triangle you had. It didn't quite fit. Check the slope of the hypotenuse on the two different parts of the triangle.

[Maghlenn3295]

the last trick: due to the positioning of the TRIANGLES, they are taking up more diagonal squares, which would produce eventually and add up to 1 extra square unit

[pokemonkiller20]

the last trick is the one who fulled me

[boomk90]

For the extra square trick, watch as he counts the 13 squares, he counts the 2nd last square as 2

[ChristosC2]

@boomk90 that would then be 12X5=60 !

[RichardBehiel]

Did anyone else see it say 420 at 0:49?

[thangkingking12345]

all his tricks are easy.

[nerkn]

it forces to buy the book. Thats only adv.

[ScienceGuyBillNye]

Cool!

[blauerninja]

great. its magic!

[qzervi]

u realise some of the red lines are bolded in the square. but the red lines are finer in the rectangle.

[grantrick1]

pause at 1:43 lol

[FunIsPhun]

we did that in math class

[swordsplayer04]

the extra square comes from the thick red line in the middle of the 8x8 grid.

[shervinrrr]

The 2 different shapes after 3:00, They must have the same area if those 4shape cover both prefectly. I belive one of them has 64 small squre and one has 65 becasue those little squares inside are not equal. (He also didn't mention that they are equal either).

Thanks for the video.

[Minertorus]

His "hahaha" made me "hahahahaha"

[fraserarts99]

what is the first trick called?

[fraserarts99]

I have murderous maths codes: how to make them and how to break them.

[jamesamaralbednell]

if you put the left and the right together they give 1 extra cubee

[bradzilaaaa]

The grandient of the hypotenuse (however u spell it) on the large triangles is less steep than those of the diagonal bits on the trapeziums, hence, that second shape isnt actually a rectangle its more of a hexagon but with such little variation on the angles it looks like a rectangle.

[laplansm]

the slopes dont match up on the square so they cannot be counted as a rectangle

[fizzypuppy]

the trick was so cool and that was awsome

[antonyjbradley]

if you pause at 3.06... you see. if the triangle on the right was straight against the bottom right bit. you can see how it dosnt work

[antonyjbradley]

Where does the extra square come from... it dosnt. i just printed off exact measurements. and cut it. it dosnt go together. if you watch carefully when he puts the supposed 65 square pieces together it dosnt match and he quickly removes them and show you what it makes.... CONMAN :)... keep an eye out for me. im going round exposing these "math tricks"...

[pludrpladr]

theres also a square puzzle where a square dissappears... but it fits perfectly on the previous square :o (im danish i dont know english math >:[ )

[bubbajiff]

what!?!

where DID that extra square come from!?!?

MY WHOLE LIFE HAS BEEN TURNED UPSIDE DOWN!!!!

AAAAHHHHHH

[muffin1102]

@bubbajiff

the slopes of the lines are not equal; looking at the original, square grid, the line that makes the triangle is 8/3, or 2.333. The line that makes the pentagon should be perpendicular to that line: it should have a slope of 3/8, or 0.375. However, it has a slope of 2/5, or 0.400. The difference between these is small, so you would hardly notice it. This small difference in slopes makes the small difference in area (1 square unit would be small compared to 64 square units).

[pikuorguk]

@bubbajiff It's a trick. Look carefully at the shapes.

[majaisavo]

@bubbajiff if you asemble it corectly you would see a gap that has area same as that extra square.

ps. sorry for my english

[tuzmor]

@bubbajiff It happens because the hypotenuse (in both pictures) isn't a straight line. Shape B goes horizontally 5 squares and vertically 2 squares while shape A goes horizontally 8 squares and vertically 3 squares. In order for the hypotenuse to be straight, they would have to have the same ratios. So in the top picture, the hypotenuse caves inwards while in the bottom picture, the hypotenuse caves outwards. (Google)

[MsCamotoe]

@bubbajiff the line is not straight on the second one

[Philipomagno]

@MsCamotoe exactly, thats the hole magic, is a milimetrical trick, learned when i was like 10 at school

[ideegeniali]

@bubbajiff The diagonal doesn't align perfectly, leaving some room in between for the extra area

[RUL1S88]

@bubbajiff

Noob start going to school.

[safdotkom]

@bubbajiff there are difference of mm which adds up to 1cm giving it to 65 when assemble it the the other way :p

[TheManUtdGuy]

the extra square is made of not completed squares

[dddin12345ddddd]

wow! The author!

[xxxpistolpetexxx]

Thanks for the lecture yesterday at Imperial College. You said that this had 12,000 views! And you were right haha! Oh and thanks for the most pathetic facts in Maths!

[u1zha]

Try Martin Gardner

[contantg]

lol the last trick is the easiest

just calculate the angles and u find the mistake

[Furry4Life13]

the grid puzzle is amazing!

[allehelgen]

by head, 7*11*13 = 1001... That's amazing, he wrote 6 letters ! Wow ...

[superfrowny]

its numbers not letters

[allehelgen]

thanks, I could'nt find that word :)

[slonopochron3000]

don't you see, 1001 times any three digit number just gives that number repeated twice, e.g. 123 -> 123123 so he didn't even have to calculate it just write the original number (given by the people) twice

[aquamarine8889]

this vid rocked the house

[CoreyZamprogno]

he sounds like a top guy

[DandyNewberg]

he came to my scool panzrocks123 brought one of his books

[panzrocks123]

he came to my school at fullbrook today

absolutly brilleiant funny and amazing tricks

[habbohotel19954]

He was at my school today. I was in fits of laughter. He is sooooo funny and sooooo good!

[Aditikhirbat3]

wow!!!

how did he do the last one!!??

hes amazing...