Maths Puzzles

# Maths Puzzles

## Maths Puzzles

Maths puzzles are the tricky concepts of maths which puzzle the mind of the students. It is used to improve the mind of the students. If the given puzzles are solved by a student, it means the student has a sharp mind and he is very genius in mathematics.

## Puzzle 1: Boat Puzzle

A farmer wants to cross a river with two of his pets, a lion and a sheep, and a bundle of grass. There is only one boat that is available for crossing the river and the farmer can cross the river with only one of his pets or bundle of grass in one go. The condition is that if he leaves the lion with the sheep, the lion will eat the sheep and if he leaves the sheep with the bundle of grass, the sheep will eat the grass. How will the farmer cross the river safely with his pets and the bundle of grass?

Similarly, we can think of the following puzzle where the concept of mathematics is used.

Solution:

## Puzzle 2: Think and Solve

Hari wants to cross a small river with his wife Pushpa and his 10 years’ old son Anuj.
Hari weighs 70 kg, his wife weighs 50 kg and his son weighs 25 kg.
There is only one boat that is available for crossing the river.
The maximum weight limit of the boat is 80 kg.
Find out how all three of them can cross the river.

Solution:

## Puzzle 3: Change Positions and Add

How can you add 8, eight times so that the answer is 1000? You can arrange 8 in any manner and at any place.

Solution:

## Puzzle 4: Code Breaker

A code is a way of writing a message in secret.
The code below is very easy.
Each letter of the alphabet is replaced by a number.
Send your message in numbers and then your friend can use the decoder to find out what it says.

The Decoder
 A B C D E F G H I J 1 2 3 4 5 6 7 8 9 10

 K L M N O P Q R S T 11 12 13 14 15 16 17 18 19 20

 U V W X Y Z 21 22 23 24 25 26

So, if I want to write 'hello' I would write 8 for H, 5 for E, 12 for L and 12 for L again and then 15 for 0.
My code would be     8     5      12     12      15
Now try and work out what this message says.

 25 15 21 1 18 5 7 5 14 9 21 19

## Puzzle 5: Diggy Digits

This puzzle is in three parts.
You need to answer all three parts.

Part 1: Use four 4's to make 44.
Part 2: Use five 5's to make 55.
Part 3: Use six 6's to make 66.

Not too difficult, but there are several ways of doing some of these.

Put four coins on a table, in a row, all tails up, like this:

1. Turn any three coins over in one go. This counts as one move.
2. You must turn any three different coins to complete one move.
3. How many moves will it take to get all the coins on heads?
3. Remember that you have to turn three coins over each move.

## Puzzle 7: Be Safe

A covid-19 hospital has 16 isolation rooms. Each room has a patient with covid-19 positive. Patient in room number 13 recovers and wants to say goodbye to each patient. He can only visit each patient once. If he visits a patient twice, he becomes covid-19 positive again. How does he do this and exit from room number 4?

## Puzzle 8: Magic Triangles

Place the digits from 1 to 9 in each of the smaller triangles of the figure without 10

repetition so that the sum of the numbers in each of the four larger triangles is 25.

Puzzle 9: Crossword Puzzle 1

Across:

1. The equality of two ratios is called ________.

4. The price after deducting discount from the marked price is called ________.

5. The interest calculated on both the principal and the accrued interest is ________ interest.

6. If an object covers equal distances in equal intervals of time, its speed is said to be ________.

8. Two quantities are said to vary directly if the increase in one quantity causes the ________ in the other quantity.

Down:

2. The set from which the values of the variable are chosen is called the ________.

(Hint: two words)

3. The set of first components of all ordered pairs which belongs to the relation R is its ________.

7. The unique element b of B associated with an element a of A is called the ________ of a.

Puzzle 10: Crossword Puzzle 2

Across

2. If the edges of a cube are doubled then volume becomes ________ times.

4. Volume and ________ are interrelated.

5. The ________ of a solid is the measure of space occupied by that solid.

Down

1. Area of the four walls of a room (rectangular or square) is called its ________ surface area.

3. The volume of a cube is 4096 m3, length of its side is ________.

Puzzle 10: Crossword Puzzle 3

Across

3. It is the measurement of the space occupied by it.

4. Volume of a cuboid = length × breadth × ________.

6. Area of a rectangle = length × ________.

9. Perimeter of a square = 4 × length of its ________.

Down

1. Perimeter of a rectangle = 2 × (________ + breadth)

2. Area of four walls of room = ________ of a floor × height of room

5. Volume of a cube = Length of an edge to the power ________.

7. It is the measure of the region enclosed by the boundary of a figure.

8. Surface area of a cuboid is the sum of the areas of all its ________ rectangular faces.