Find the Next Number in the Sequence

2 9 3 1 8 4 3 6 5 7 ?

How many triangles can you find in this given picture?

Can you find a seven digit number which describes itself. The first digit is the number of zeros in the number. The second digit is the number of ones in the number, etc. For example, in the number 21200, there are 2 zeros, 1 one, 2 twos, 0 threes and 0 fours.

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.

What is the largest number you can write with just 3 digits?

Can you complete the sequence?

192, 021, 222, 324, 252, 627, 2__, 9__?

A sundial has the fewest moving parts of any timepiece. Which has the most?

Can you replace the X (both small and big x) with the numbers between 1 to 19 such that all the rows of 3 numbers between X (big x) sum to 23?

Can you name four days which start with the letter 'T'?

How will you measure 15 minutes using two hourglasses of 7 minutes and 11 minutes respectively?