# 100+ Challenging math riddles to keep your mind sharp

#### Count the number of squares - Math Riddle

###### 16. Math Riddles

Count the number of squares in the given figure?

Explanation :

• N1: The number of simplest squares (1 component).
• N2: The number of squares with two components.
• N4: The number of squares with four components.
• N7: The number of squares with seven components.
• N9: The number of squares with nine components.
• N17: The number of squares with seventeen components.

Now, we can use these variables to express the total number of squares in the figure:

Total number of squares (T) = N1 + N2 + N4 + N7 + N9 + N17

From the provided information, we have:

N1 = 13 (simplest squares) N2 = 4 (squares with two components) N4 = 4 (squares with four components) N7 = 4 (squares with seven components) N9 = 1 (square with nine components) N17 = 1 (square with seventeen components)

Now, we can calculate the total number of squares:

T = 13 + 4 + 4 + 4 + 1 + 1 T = 27

So, the total number of squares in the figure is 27, as you've correctly calculated.

#### 2 5 9 - 20 35 Easy Missing number Math Riddle

###### 18. Math Riddles

What is the missing number in the sequence 2, 5, 9, 14, 20, ?, 35

Explanation :

Let's define the sequence as S(n), where "n" is the position in the sequence.

S(1) = 2

To find the pattern, you correctly observed the following:

S(n) = S(n-1) + n + 1

This equation represents the mathematical pattern where each term in the sequence is obtained by adding the previous term (S(n-1)) to the position in the sequence (n) plus 1. This is why we have:

• S(1) = S(1-1) + 1 + 1 = 2
• S(2) = S(2-1) + 2 + 1 = 5
• S(3) = S(3-1) + 3 + 1 = 9
• S(4) = S(4-1) + 4 + 1 = 14
• S(5) = S(5-1) + 5 + 1 = 20
• S(6) = S(6-1) + 6 + 1 = 27
• S(7) = S(7-1) + 7 + 1 = 35

So, using this pattern, we can find the missing number in the sequence:

S(6) = S(6-1) + 6 + 1 = S(5) + 7 = 20 + 7 = 27

The missing number is 27, and the sequence follows the pattern you've described.

#### Guess the Number - Math Riddle

###### 20. Math Riddles

Can you solve this?

Explanation :

The pattern is,
First Method,
1*4+1  = 5
2*5+2  = 12
3*6+3  = 21
11*8+8 = 96

Second Method,
1+4=5
2+5=12
3+6=21
4+7=32
5+8=45
6+9=60
7+10=77
8+11=96

#### Person is 10 years old -Math riddle

###### 22. Math Riddles

In 1990, a person is 15 years old. In 1995, that same person is 10 years old. How can this be?

Explanation :

The time must have been before Christ (BCE).

According to the Gregorian calendar, the Earth's timeline can be divided into two eras: Before Christ (BCE) and Anno Domini/Common Era (AD/CE).
In BCE, the years are reversed, so 1990 comes after 1995, and so on.
In the case of AD/CE, the years are listed in chronological order, so 1990 comes before 1995, and so on.

So, if someone was 15 years old in 1990, he or she would have been 10 years old in 1995, 5 years earlier.

#### Guess the family member - Math riddle

###### 23. Math Riddles

Mom and dad have four daughters, and each daughter has one brother.

How many people are in the family?

Explanation :

In this family, the equation can be represented as:

Total Family Members (7) = 1 Mom + 1 Dad + 4 Daughters + 1 Son

Mathematically:

7 = 1 + 1 + 4 + 1

This equation illustrates the family structure and the count of each family member:

1 Mom
4 Daughters
1 Son
When you add them up, you get the total of 7 family members. So, mathematically, there are indeed 7 people in the family, as described in the riddle.

#### What is the value of 1/2 of 2/3 of 3/4.....- Math Riddle

###### 24. Math Riddles

What is the value of 1/2 of 2/3 of 3/4 of 4/5 of 5/6 of 6/7 of 7/8 of 8/9 of 9/10 of 1000?

Explanation :

Certainly, let's provide a mathematical explanation for the value of the expression:

1/2 * 2/3 * 3/4 * 4/5 * 5/6 * 6/7 * 7/8 * 8/9 * 9/10 * 1000

Multiply it by the second fraction, 2/3:

(1/2) * (2/3) = 2/6 = 1/3

Now, multiply the result (1/3) by the next fraction, 3/4:

(1/3) * (3/4) = 3/12 = 1/4

Continue this process by multiplying by each successive fraction:

(1/4) * (4/5) = 4/20 = 1/5

(1/5) * (5/6) = 5/30 = 1/6

(1/6) * (6/7) = 6/42 = 1/7

(1/7) * (7/8) = 7/56 = 1/8

(1/8) * (8/9) = 8/72 = 1/9

(1/9) * (9/10) = 9/90 = 1/10

Now, we have:

(1/10) * 1000 = 100

So, mathematically, we've shown that the expression simplifies to 100. This demonstrates that a series of fractions can be progressively simplified, resulting in a clear and straightforward answer.

#### The Bare Feet Kids-Math riddle

###### 25. Math Riddles

There are 12 kids in a classroom. 6 kids are wearing socks and 4 are wearing shoes. 3 kids are wearing both.

How many are bare feet?

Explanation :

As we know 3 kids are wearing both,
So only 3 kids are wearing only socks(6 - 3 = 3)
and 1 is wearing only shoes(4 - 3 = 1).
So, in total 3 + 3 + 1 = 7.
Now 12 are there, so 12 - 7 = 5 kids are in bare feet.

#### How many coffins are open - Math Riddle

###### 26. Math Riddles

There are 500 coffins and 500 men who need them. The undertaker asks the first man to go to every coffin and open them. Then he tells the second man to go to every one and close it. The third one goes to every third coffin and so on.

How many are open?

Explanation :

Certainly, let's provide a mathematical explanation for the answer:

Initially, we have 500 coffins, and each of them is open.

The process involves 500 men who will perform actions on the coffins. We need to determine which coffins remain open.

To find the coffins that stay open, we consider the square root of the total number of coffins, which is √500.

Calculate the square root of 500:

√500 ≈ 22.36

The square root gives us a decimal value, but for this puzzle, we are interested in the whole number part, which is 22.

So, 22 coffins will remain open because they are the ones that have an odd number of actions performed on them.

Mathematically:

√500 ≈ 22.36

Therefore, the answer is indeed 22 coffins that stay open.

#### Clothing Store in Dallas - Math riddle

###### 27. Math Riddles

There is a clothing store in Dallas. The owner has made his own method of pricing items. A vest costs \$20, socks cost \$25, a tie costs \$15, and a blouse costs \$30. Using the method,

How much would a pair of underwear cost?

Explanation :

Underwear would cost 45 dollars, since there are 9 letters in "Underwear.“

The cost of each item is solved by taking the number of letters in the item and multiplying it by 5.
Example,

V E S T = 4 letters * 5 = 20
S O C K S = 5 letter * 5 = 25
T I E = 3 letters * 5 = 15

So,
U N D E R W E A R = 9 letters * 5 = 45

#### Seven People handshakes-Math riddle

###### 28. Math Riddles

If seven people meet each other and each shake hands only once with each of the others,

How many handshakes happened?

Explanation :

Certainly, let's provide a mathematical explanation for the number of handshakes:

To calculate the total number of handshakes that occur when seven people shake hands as described in the riddle, we can use a summation.

We start with the first person, who shakes hands with six other people. This can be represented as:

1st person shakes hands with 6 people = 6 handshakes

Then, the second person shakes hands with the remaining six people (excluding the first person), so:

2nd person shakes hands with 5 people = 5 handshakes

The third person shakes hands with 4 people:

3rd person shakes hands with 4 people = 4 handshakes

This pattern continues until the last person, who shakes hands with only one person:

7th person shakes hands with 1 person = 1 handshake

Now, to find the total number of handshakes, we simply sum up these individual handshakes:

Total handshakes = 6 + 5 + 4 + 3 + 2 + 1

Total handshakes = 21

Therefore, there are indeed 21 handshakes in total when the seven people follow the described handshake pattern.

#### Cheaper Movie Ticket-Math riddle

###### 29. Math Riddles

If you go to the movies and you are paying, is it cheaper to take one friend to the movies twice or two friends to the movies at the same time?

Explanation :

It's cheaper to take two friends at the same time. In this case, you would only be buying three tickets, whereas if you take the same friend twice, you are purchasing four tickets.

#### Bees and Flowers Logic -Math riddle

###### 30. Math Riddles

There are some lotus flowers in a pond and some bees are hovering around.
If one bee lands on each flower one bee will be left,
If two bees land on each flower one flower will be left,
Then the number of flowers and bees respectively are

How many flowers and bees are there?

Explanation :

Let the number of flowers  = x
if one bee lands on each flower Then one bee will be left So number of bees in this case =x*1+1=x+1
If two bees land on each flower then one flower will be left  so number of bees in this case
=(x-1)*2=2x-2
we have
x+1=2x-2
x=3
Number of flowers  =3
Number of bees =x+1=3+1=4