### #1 - Square Root 12345678987654321 Puzzle

The square root of number 121 is "11". What is the square root of number "12345678987654321." ?

111111111

It is a very popular square root series i.e.
Square root fo number 121 is 11
Square root fo number 12321 is 111
Square root fo number 1234321 is 1111 and so on....

### #2 - Good Age Riddle

Lena Dunham , Allison Williams, and Jemima Kirke are 3 daughters of a good mathematician "Geroge".
When I asked George the age of their daughters. He replied "The current age of her daughters is prime. Also, the difference between their ages is also prime."

How old are the daughters ?

Lena Dunham : 2 , Allison Williams : 5 and Jemima Kirke : 7

Age diff : 7-2 is 5 , 7-5 is 2 and 5-2 is 3 which all are prime numbers

### #3 - Popular Algebraic Equation Puzzle

0 0 0 = 6
1 1 1 = 6
2 2 2 = 6
3 3 3 = 6
4 4 4 = 6
5 5 5 = 6
6 6 6 = 6
7 7 7 = 6
8 8 8 = 6
9 9 9 = 6

You can use any mathematical symbols in the space provided to make all above algebraic expressions true.

(0! + 0! + 0! )! =6
(1! + 1! + 1! )! =6
2 + 2 + 2 = 6
3 * 3 - 3 = 6
4 + 4 -sqrt(4) = 6
5 + 5 / 5 = 6
6 + 6 - 6 = 6
7 - 7 / 7 =6
8 - sqrt(sqrt(8+8) = 6
(9 + 9) / sqrt(9) = 6

### #4 - Number Trivia

Can you find out which number multiplied by itself will give the output as 12345678987654321 ?

1 * 1 = 1
11 * 11 = 121
111 * 111 = 12321
1111 * 1111 = 1234321
.
.
.
111111111 * 111111111 = 11=2345678987654321

### #5 - Who Survives Hard Logic Puzzle

Suppose there are 100 people standing in a circle. The first person has a gun in hand. What he has to do is shoot the second person and then pass the gun to the third person. Now, the third person kills the fourth person and gives gun to the fifth person.

This process is carried till there is only one person surviving. Can you find out who survives at the end ?

73rd

There is a simple logic behind solving this question. If the number of people are a power of 2, then the last person standing will be the person who started it.
Now, here we have 100 people. Thus, we will take the highest power of 2 which is less than the total number which is 64.
100 - 64 = 36.
This means that 36 people are killed.
If you go on with the series of even numbers, the 36 people will end at 72 (2, 4, 6, ..., 72). Thus the gun will be in the hand of 73rd person. Now the remaining people are 64 which is the power of 2. Thus the person who will survive in the end will be the 73rd person since he is starting it.

### #6 - Physics Maths Who Dies Question

In the following picture, E is going to slide the object down and as per the terrain and the physics, the round object is going to travel all the way till the end. Now, can you analyze who all people will die when it happens?

As you can see, the person at D dies straight through the object directly. The object then travels further and the see saw thing kills the person at the C as it has spikes below that. Upon falling, over the see saw, the blue object lifts up and then kill the person at B.The solution ends here, but just for fun, The E stands for Ebola and thus the person at A dies as well.Thanks to 9gag for this gif.

### #7 - Solve Mathematical Equation

Can you solve below mathematical equation ?

2^1234 - 2^1233

2^1233

### #8 - Math Brain Twister

100^2 - 99^2 + 98^2 - 97^2 + 96^2 - 95^2 + ... + 2^2 - 1^2 = ?

Since you can notice that there are fifty pairs of n^2 - (n-1) ^2,
n^2 - (n-1)^2 = n + (n - 1)

Thus 100^2 - 99^2 + 98^2 - 97^2 + 96^2 - 95^2 + ... + 2^2 - 1^2 can also be written as
100 + 99 + 98+ ... + 2 + 1 = (100 x 101)/2 = 5050

### #9 - Maths Logic Riddle

It can be easily calculated that the digits 0 to 9 can be arranged into 3628800 distinct ten-digit numbers.

But I also know how many of these numbers are prime.

Do you?

Zero

The sum of numbers from zero to nine is 45 and can be divisible by 3 and 9.

### #10 - Maths Magic Puzzle

A number can be multiplied by multiple of nine
i.e 9 18 27 36 45 ...

and the resulting number consist of only one digit.

Can you identify the number ?

12345679

12345679 × 9 = 111111111 (only 1s)
12345679 × 18 = 222222222 (only 2s)
12345679 × 27 = 333333333 (only 3s)
12345679 × 36 = 444444444 (only 4s)
12345679 × 45 = 555555555 (only 5s)