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

what does this below rebus represent identXQQQQQME

Jim and Sarah are in a long-distance relationship. Jim buys an engagement ring for Sarah and wants to mail it to her. Unfortunately, the only way to ensure the ring will be received is to place a lock on the package. Jim has locks and Sarah has locks, but neither has keys for each other’s locks. How can they make sure the ring isn’t stolen?

One is to three as three is to five and five is to four and four is the magic number.
What is the pattern?

What is the next number in this series?

4,12,84,3612....

Find three numbers such that

* When we multiply three numbers, we will get the prime numbers.
* The difference between the second and the first number is equal to the third and second.

If I remove one from eleven it becomes Ten and if I remove one from nine also becomes Ten. How?

What work can one never finish?

Prove that the below maths equation is true.

8 + 8 = 91

A mules travels the same distance daily.
I noticed that two of his legs travels 10km and the remaining two travels 12km.
Obviously two mules legs cannot be a 2km ahead of the other 2.

The mules is perfectly normal. So how come this be true ?