What has six faces, but does not wear makeup, has twenty-one eyes, but cannot see?

There are 2 sand hourglasses.

The small one can measure 5 hours and the large one can measure 7 hours.

How can we measure 16 hours with 2 sand hourglasses running together ?

You want to boil a two-minute egg. If you only have a three-minute timer (hourglass), a four-minute timer and a five-minute timer, how can you boil the egg for only two minutes?

If you remove one from eleven, it becomes ten. If you remove one from nine, it becomes ten.

How is this possible?

Use the digits from 1 up to 9 and make 100.

Follow the rules.
=> Each digit should be used only once.
=> You can only use addition.
=> For making a number, two single digits can be combined (for example, 4 and 2 can be combined to form 42 or 24)
=> A fraction can also be made by combining the two single digits (for example, 4 and 2 can be combined to form 4/2 or 2/4)

Question: how can we do this?

Make eight squares by moving only two matchsticks.
Note- Square can be of different sizes.

I have Rs.50 and I spend it in the way as below.

Replace the question mark with the number below given a simple math problem.

How many letters are in the alphabet?

I know a nine-letter word having only one vowel.
Do you ?