100+ Challenging math riddles to keep your mind sharp

Answer:27

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.

Explanation :  

Answer:27

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.

Explanation :  

45  By using forward letter position, we have,
CUP = C + U + P = 3 + 21 + 16 = 40.
Similarly, KITE = K + I + T + E = 11 + 9 + 20 + 5 = 45.

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

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.

Answer: 7

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
1 Dad
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.

Answer: 100

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

Start with the first fraction, 1/2.

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.

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.

Answer: 22

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.

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 

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.

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