Replace the question mark with the correct number, given the pair of numbers exhibits a similar relationship?

? : 3839 :: 11 : 1209

Can you think of a smallest +ve number such that if we shuffle the digits of the number, the new number becomes double the original number?

What does this mathematical rebus means ?

Quickly Solve this riddle

7 - 4 + 3 * 0 + 1 = ?

Can you find out the smallest number that can be conveyed as the sum of three squares in three unique ways?

A 52% bias toss for head using the 51% tail bias coin was done to obtain a fair result.

Can you find how bias is the floor in this case?

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?

Below, you will find the mathematical proof that 10 equals 9.99999?. But is that possible or there is something wrong about it? Can you find the error?

x = 9.999999...
10x = 99.999999...
10x - x = 90
9x = 90
x = 10

In case you were starting to feel confident, this one was meant for third graders in Vietnam. The answer is 66, but we don't blame you for scratching your head about how they got there.

Look at this sequence from top to bottom. What is the next number in the sequence?
1
11
21
1211
111221
312211