I am a prime number.
The double of myself is equal to the square of me.

which number am I?

Check out the number list below and find what number comes next in the sequence.

111 , 113 , 117 , 119 , 123 , 137 , ?

What three numbers, none of which is zero, give the same result whether they’re added or multiplied?

Get total of 120 by using five zeros 0,0,0,0,0 and any one mathematical operator.
Do you ?

Find a 9-digit number, which you will gradually round off starting with units, then tenth, hundred etc., until you get to the last numeral, which you do not round off. The rounding alternates (up, down, up ...). After rounding off 8 times, the final number is 500000000. The original number is commensurable by 6 and 7, all the numbers from 1 to 9 are used, and after rounding four times the sum of the not rounded numerals equals 24.

How many triangles are there on the puzzle below?

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

What's a single-digit number with no value?

All of Jacob's shoes are red except two.
All of Jacob's shoes are green except two.
All of Jacob's shoes are yellow except two.

How many shoes does Jacob have?

If we add four times the age of John four years from now to five times his age five years from now we get ten times his current age.

How old will John be two years from now?