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

If 5 cats catch 5 mice in 5 minutes, how long will it take one cat to catch a mouse?

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

? : 3839 :: 11 : 1209

If "P" means "-", "Q" means "/", "R" means "+", and "S" means "*" then find the value of the following:

21 Q 7 R 9 S 10 P 13

How do you go from 98 to 720 using just one letter?

Which three-digit number, made of consecutive digits, like 567, is 2 less than a cube and 2 more than a square?

I want to fill my bucket using both cold and hot water.
I have two taps for both cold and hot water. The hot water tap fills the bucket in exact 6 hours and the cold water tap fills the bucket in exact 4 hours.
I turn both of them simultaneously but I forgot to turn off another tap which removes the water out of the bucket. This tap can empty the bucket in 12 hours.

How Long will it take to fill the bucket?

We have arranged an array of numbers below. What you have to do is use any kind of mathematical symbol you know excluding any symbol that contains a number like cube root. You can use any amount of symbols but you have to come up with a valid equation for all of them.

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

There are two candles. Both will only burn exactly for an hour. How will you use these two candles to measure forty-five minutes?

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