Des Énigmes Mathématiques Plus Faciles Qu’elles N’en Ont L’air

Sympa

Salut à tous les amateurs de casse-têtes ! Prêts à tester votre puissance cérébrale avec des énigmes mathématiques bien plus simples qu’elles ne le paraissent ? Nous avons tout un tas de questions amusantes et difficiles qui vous feront vous sentir comme un génie lorsque vous les résoudrez. Alors rassemblez vos amis ou votre famille et voyez qui peut les résoudre le plus rapidement. Plongez avec nous et voyons lequel d'entre vous saura maîtriser ces défis mathématiques faussement simples !  Animation créée par Sympa. ---------------------------------------------------------------------------------------- Musique par Epidemic Sound https://www.epidemicsound.com   Pour ne rien perdre de Sympa, abonnez-vous!: https://goo.gl/6E4Xna​ ---------------------------------------------------------------------------------------- Nos réseaux sociaux : Facebook: https://www.facebook.com/sympasympacom/ Instagram: https://www.instagram.com/sympa.officiel/  Stock de fichiers (photos, vidéos et autres): https://www.depositphotos.com https://www.shutterstock.com https://www.eastnews.ru ----------------------------------------------------------------------------------------  Si tu en veux encore plus, fais un tour ici:  http://sympa-sympa.com

Transcript

00:00We will start with a little math in English. You have 10 seconds to make the number 7 pairs.

00:19It has nothing to do with math in English. To make 7 pairs, you just have to remove the letter S from the word 7.

00:26Well, now we're going to complicate things. 2, 4, we skipped dinner. Why?

00:48Because they are 8 and ate in English is the past of eat.

00:55A last one to finish warming up. Tell me what numbers are still in motion.

01:13Roman numbers. Because in English, roaming means itinerant. Let's get down to business.

01:20Let's test your logic, shall we? Look at this sequence of numbers.

01:254, 6, 9, 6, K14, 6. As you can see, a number is missing. What number logically follows this series?

01:336, 17, 19, 21.

01:49If you have chosen the number 19, congratulations. You see, we add 5 each time. 4 plus 5, 9, 9 plus 5, 14, and 14 plus 5, 19.

02:00The 6 placed between the other numbers do not change. They only somehow frame or separate the numbers of the series.

02:10Now look at this picture. How many triangles are there?

02:15Wait, I'll help you a little. So here are 7, 8, 12, 18.

02:32The correct answer is 18. Look, here's how to count. There are very small triangles at the top and then larger ones.

02:41Well, this is not a riddle, but a little magic trick to make you the fastest in your class.

02:48If you have to multiply a number from 1 to 10 by 9, you need nothing but your hands.

02:54Place your two palms in front of you and assign a number to each finger, as shown on the screen.

02:59If you have to multiply 3 by 9, fold your finger number 3.

03:04On the right, you have 7 unfolded fingers. This is the first part of the answer.

03:09On the left, only 2. This is the second part.

03:12There you go, 9 times 3 equals 27.

03:18So, do you like reductions? If so, you must be quick to calculate how much money you will save.

03:24To calculate the reduction you will get in a store without using a calculator, use this trick.

03:30For example, to find what 5% of 235 represents, follow this method.

03:35Step 1. Find 10% of the total. It's easy, you just have to put a point or a comma before the last number.

03:42235 becomes 23.5.

03:45Step 2. Keep in mind that 5% represents half of 10%.

03:49Divide 23.5 by 2. The result is 11.75. This is also the answer to the original equation.

04:01Very well, now here is another math trick.

04:05So, 1% of B is equal to B% of A. For example, 9% of 30 is equal to 30% of 9.

04:12That's all, this trick was really very short.

04:15You will probably thank me one day when you will have used this trick in a test.

04:20A math trick to save your party.

04:24What is bigger, a pizza of 45.72 cm or two pizzas of 30.48 cm?

04:32You have 10 seconds to think.

04:47There are actually two possible answers.

04:49According to the geometry, the surface of two pizzas of 30.48 cm is equal to 1458.06 cm2,

04:59while that of 45.72 cm is equal to 1638.71 cm2.

05:08So, from this point of view, you would better choose the pizza of 45.72 cm.

05:13But, and, geometry and cooking are two completely different things.

05:18It is the weight that counts here. The higher the weight, the more calories there are.

05:22So you know what to choose, and there will be enough pizza for everyone.

05:28Well, let's take a short break and discover another funny riddle.

05:32Number 4 wanted to go to the nightclub, but the security service did not let him in. Why?

05:49Because he was too square. No luck, friend.

05:57In the world of geometry, everyone says that this triangle, Jack, is impolite.

06:02What could Jack, the impolite triangle, say to Jerry, the circle?

06:19Jerry, you suck. Because it looks like a zero. It's not very polite, but it's just geometry.

06:29Do you know what snake bears the most mathematical name?

06:45The python.

06:49Let's get back to more serious things. Suppose you have to prove that 6 plus 7 is 1. How do you do it?

07:09No, it's not magic. You just have to change perspective.

07:14Let's say that these are not numbers, but hours. Do you see where I'm coming from?

07:19Yes, 6 o'clock in the morning plus 7 equals 1 o'clock in the afternoon.

07:26Well, something more difficult. What if I told you that 2 plus 2 equals 5?

07:31Yes, you will send me back to elementary school, but I can prove it to you. Be careful.

07:37Technically, it is incorrect, but there are funny methods to prove the opposite.

07:43Here is the simplest method. Let's say that 0 equals 0.

07:47Now, 0 can result from the subtraction of a number by itself.

07:51So, let's suppose that the two numbers on the left side and on the right side are 4 and 10.

07:56So, 4 minus 4 equals 10 minus 10.

07:594 can be written as 2 squared, and 10 can be written as 2 multiplied by 5.

08:05By solving the equation further, we get 2 squared minus 2 squared equals 2 times 5 minus 2 times 5.

08:12And when we arrange things a little, we get 2 minus 2, 2 plus 2 equals 5, 2 minus 2.

08:19By canceling 2 minus 2 on both sides, we get 2 plus 2 equals 5.

08:24That's it, it's proven. But don't try this during your math class.

08:28I don't think your teacher will be very impressed. It's just for fun.

08:34This is not a mathematical riddle, but rather another magic trick that can be useful to you during an exam.

08:41Here is how you can quickly calculate the square of a number with two numbers, ending with 5.

08:47Let's use the number 35 as an example.

08:49Step 1. Multiply the first number by itself plus 1.

08:53Step 2. Add a 25 at the end.

08:5535 squared equals 3 multiplied, 3 plus 1, and 25.

08:5912 and 25 equals 1225.

09:0235 squared equals 1225.

09:05Cool, right?

09:08Here is another multiplication trick.

09:11To easily multiply any number by 5, just divide this number by 2 and then multiply it by 10.

09:18For example, let's multiply 64 by 5.

09:20Step 1. Divide 64 by 2 equals 32.

09:24Step 2. Multiply 32 by 10.

09:27Just add a 0 at the end.

09:29You get 320.

09:31And it only took you 5 seconds.

09:35A little more magic.

09:37You already know how to multiply by 5 super easily.

09:40And you can do the same thing with 6.

09:42But be careful, it only works for odd numbers.

09:45So, let's see how it works.

09:48Let's say you have to multiply 4 by 6.

09:50First, you have to divide 4 by 2.

09:52You get 2.

09:54Then, place 4 after 2, and you get 24.

09:57This is the final answer.

09:59This could not work with bigger numbers.

10:02It is better to take the multiplication table by heart.

10:07I can read your mind.

10:09If you don't believe me, think of a number.

10:12Make it simple, because you will have to do some math.

10:15And you will probably need a calculator to play this game with me.

10:19Good. So, you think of a number.

10:22Now, multiply it by 3.

10:24Done? OK.

10:25Now, add 6.

10:27The next step, you have to divide this number by 3.

10:30Now, subtract the number you thought of from the resulting number.

10:34Let me guess.

10:35You got 2 as a result, didn't you?

10:38It's not magic.

10:39It's just a good math trick.

10:41And it works with any number.

10:45If you have ever had trouble learning all the numbers of the pi number,

10:49forget it.

10:50There are billions of them.

10:52But, there is a trick to remember at least 7.

10:56Simply say,

10:58How I wish I could calculate pi.

11:01There are 3 letters in how.

11:031 in i.

11:044 in wish.

11:051 again in i.

11:075 in cooled.

11:089 in calculate.

11:09And 2 in pi.

11:11You get 3.141592.

11:17One last one for the road.

11:195 people build a barn in 8 hours.

11:22How long will it take 12 people to build a barn?

11:39No time at all.

11:40Why would they build a new barn if the first 5 have already done it?

11:44Let people rest a little.

11:46And it has nothing to do with math.

11:48We humans are quite complicated like that.

11:51And we do not obey the math rules.

11:54What if these 12 people formed 2 teams of 6

11:57and started a match instead of building a barn?

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