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

John left on a horse on Thursday , was gone for two days, and came back on Thursday after completing his work. How did that happen?

Take one out and scratch my head, I am now black but once was red. What am I?

You have two strings whose only known property is that when you light one end of either string it takes exactly one hour to burn. The rate at which the strings will burn is completely random and each string is different.

How do you measure 45 minutes?

Can you write down eight eights so that they add up to one thousand?

I am weightless, but you can see me. Put me in a bucket, and I'll make it lighter. What am I?

A clock loses 10 minutes each hour. If the clock is set correctly at noon, what time is it when it reads 3 PM?

What 8 letter word can have a letter taken away and it still makes a word. Take another letter away and it still makes a word. Keep on doing that until you have one letter left. What is the word?

I go up and I go down.
I go up towards the beautiful sky and down toward the green ground.
I am present tense.
I am past tense too
Children love me.

Who Am I?

Can you find the least possible number such that

If the number is divided by 3, it gives the remainder of 1;
If the number is divided by 4, it gives the remainder of 2;
If the number is divided by 5, it gives the remainder of 3;
If the number is divided by 6, it gives the remainder of 4.