prolog

Chapter 1: Logical Problems
_ Are you smarter than an eleven-year-old?

※ Sample Question 1
001 How to cross the river safely with a wolf, a goat, and a cabbage?
002 How can three friends and their sisters safely cross the river?
003 How can four friends safely cross the bridge while holding torches?
004 Guessing the complex family relationships of two mothers and two sons
005 How many people are invited to a small dinner party?
006 Finding the Truth Teller Among Liars
007 What is the name of the driver among Smith, Jones and Robinson?
008 Who skipped the meeting and went to the cinema?
009 Einstein's Mystery, Born After Einstein's Death
010 Five houses, 15 hints, which house has a zebra?
011 How can the book left behind by Caliban be divided equally among three people?
012 Who should the Good Guy, the Bad Guy, and the Weird Guy target?
013 How to properly label a fruit that is incorrectly attached?
014 Salt, Pepper, Relish Salt, Pepper, Relish
015 Who won the world's first game of rock-paper-scissors?
016 Find the girl with the dirtiest face among the two girls.
017 How can I notice the soot on my face sooner?
018 40 cheating husbands and their wives who punish them
019 Can you close your eyes and guess the color of the hat you took out of the box?
020 Guess the secretly written number with minimal hints
021 Singapore Find Cheryl's Birthday, Even a Ten-Year-Old Can Guess
022 Dennis' Birthday Problem: "I didn't know it before, but now I do."
023 Guessing the ages of three children with very little information
024 What bus number did you guess from the conversation with the wizard sitting next to you?
025 Turn over the card and prove the proposition.

Chapter 2 Geometry Problems
_ Are you a person who likes shapes?

※ Sample Question 2
026 Mark the exact halfway point with an unmarked ruler
027 Rope surrounding the Earth and animals passing under it
028 Find the height of the stick using the 101m belt.
029 Can you tell the direction of a bicycle just by looking at its tread marks?
030 Guess the direction the bicycle moved using only the picture in the picture.
031 How many times does a small circle have to turn to make one full circle?
032 Guess the order of the eight stacked pieces of paper
033 Divide a large square made up of 16 squares in half.
034 How can two shapes of different shapes be the same size?
035 Compare the radii of five different sized circles and a large circle.
036 Compare the sizes of three circles and a large circle.
037 Randomly arranged tatami mats, step on them all and walk over them.
038 How to fill 30 squares with 2×1 tatami mats
039 Arrange 2×1 tatami mats so that straight lines do not cross each other.
040 The perfect way to avoid stairs and lay tatami mats
041 How to Cover a Room with Tatami Mats Without Building Stairs in the Corners
042 Draw the side of the building by guessing only the top and front.
043 If you remove one nail from a picture frame hanging on two nails, will the picture frame fall?
044 Find the volume of a napkin ring using its length.
045 Finding the missing value in a shape using a few clues
046 Shikaku Puzzle: Divide a Box into Rectangles and Squares
047 A slider link that connects points to create a single ring
048 Heru Golf is a game where you move the ball by the number of numbers and put it in the hole.
049 Akari Puzzle: Inserting Light Bulbs to Light Up the Grid
050 A dark room with one light and shadows

Chapter 3 Practical Issues
_ Are you smarter than a twelve year old?

※ Sample Question 3
051 How many chickens and chicks can you buy with 100 coins?
052 How many ducks, pigeons, and hens can you buy with 100 coins?
053 Buy exactly 7-Eleven items at 7-Eleven
054 Can you pour 4L of wine using three different sized jugs?
055 Can you measure 6L of water with two buckets?
056 If you mix coffee and milk alternately, which will become more abundant?
057 Let's mix 1L of water and 1L of wine in equal proportions.
058 Measuring 15 minutes with a 7-minute and 11-minute hourglass
059 Measuring time using two fuses
060 How to change the odds of an imperfect coin to 50/50
061 Dividing flour with a two-arm scale and two weights
062 Guessing the number of weights using a two-arm scale set
063 11 identical coins and a 12th counterfeit coin
064 Can you find the fake coin tower by weighing it on a scale?
065 How many ships did the passenger ship from Le Havre to New York encounter?
066 How does flight time change when the wind blows?
067 Make the numbers on the odometer and tripmeter the same
068 If you overtake someone in a race, what place will you be in?
069 Who will win the marathon, Constance or Daphne?
070 If a potato with 99% moisture becomes a potato with 98% moisture, what will its weight be?
071 Which of the two ways to increase your salary is the higher way?
072 When a stick is cut arbitrarily, what is the length of the short stick?
073 Number of times Edward and Lucy shook hands with eight guests
074 Guess the number of attendees based on the number of handshakes between Edward and Lucy at the party.
075 What is the probability that 100 people in a movie theater will sit in the correct seats?

Chapter 4 Problems Using Props
_ A classic puzzle game that takes you through the ages using the tools at your disposal.

※ Sample Question 4
076 Six coins and a seventh coin that fits inside them
077 Converting a triangular array of coins into a linear array
078 Change H made from eight coins to O
079 Place five coins at equal distances from each other.
080 Ten coins, five in a row, and three coins in a row
081 How to always win in the coin-on-the-table game?
082 Group the same coins in four turns
083 Divide eight coins into four in four turns
084 Can the frog and toad swap places?
085 Solitaire problem: remove coins arranged in a triangle
086 Can you tell the front and back of a coin in the dark?
087 How to win without fail in the game of picking up 100 coins one by one
088 Let the coin escape without dropping the matchstick.
089 Making eight equilateral triangles into four equilateral triangles
090 Twelve matchsticks that change shape freely
091 Various triangles made with six matchsticks
092 A network of matchsticks intertwined with each other
093 Shape with 12 matchsticks meeting at all points
094 How to make two fences with 20 matchsticks
Fold the stamps numbered 095 in order.
096 How many ways are there to connect and tear four stamps?
097 Putting the shattered chessboard back together
098 Folding a cube into eight square rings
099 Simple but Nearly Impossible Vinyl Braiding
Tangloid that untwists a string without rotating 100 pieces of cardboard

Chapter 5: The Number Game
_ Are you smarter than a thirteen-year-old?

※ Sample Question 5
101 What is the sum of nine ten-digit numbers that appear symmetrical?
102 Think like Gauss and add 24 numbers
103 Add 100 numbers by thinking like Gauss
104 A puzzle formula made up of only squares
105 Ghost equations made up of only squares
Fill in the numbers to make the sum of 106 numbers constant
107 Make 0 to 9 using four 4s
108 Columbus Problem with Seven Numbers and Eight Dots
Making 24 with 109 3 and 8
110 Four-Digit Numbers and Their Own Rules
Follow the arrows according to the number 111 rules 1
Follow the arrows according to the number 112 rules 2
Follow the arrows according to the number 113 rules 3
114 A dictionary consisting solely of numbers
115 The Three Troublesome Witches
116 Multiplication Problems of Odd and Even Numbers Written in the Alphabet
How many letters are there like 117? A crossword puzzle that counts you.
118 The world's only ten-digit magnetic technology number
How many numbers are there in a 119-digit number system?
120 ten-digit numbers, ten hints
Find the four-digit number that multiplies 121 by 4 to make a handstand
122 multiplying by 2 moves the number from back to front
123 Nine numbers raised to the power of ninth
124 Infinitely continuing powers of 2
125 Infinitely many 0s

Answer and explanation
List of puzzles and their sources

Think differently, think again
Then you will get the answer!

This book is divided into five chapters, each containing 25 problems, and is organized by topic, including logic, geometry, practical skills, small items, and mathematics.
The 125 puzzles are exciting, with puzzle makers representing the East and the West competing to find the best puzzle.
The questions are usually arranged chronologically, but the level of difficulty varies greatly.
When solving a problem, creative thinking is more important than specialized knowledge or difficult mathematical theories.
Some of the questions can be answered by even a ten-year-old Singaporean.
That doesn't mean anyone can solve it.
Some problems are so difficult that only three out of 300,000 people took the SAT in 1982 could answer them correctly.
There is also a problem created by Einstein that only 2% of the world can solve.
For problems that are so difficult that you can't solve them even if you stay up all night, I put a little 'brain bomb' sign on them.
At the end of the book, there are detailed explanations to help you understand complex issues easily.

The best thing about puzzles is that they set tangible goals and give you a sense of satisfaction when you achieve them.
As you solve problems one by one, from easy to difficult, you will find yourself immersed in them and all distracting thoughts will disappear.
Take a moment to delve into the world of puzzles from Alex Bellos, one of our generation's greatest storytellers.
If you keep thinking about it, the difficult problems in life will disappear and you will develop a positive outlook on life.


“The best puzzles are like poems.
It sparks interest with elegance and simplicity, ignites our competitive spirit, and tests our ingenuity.
… puzzles may seem like a forced, trivial pastime, but the strategies used to solve them develop the skills needed to tackle the many challenges we face in life.”