A maths symbol is hidden in the below Bar Graph. Can you decipher it?

In a jungle where there are no street lights or any other artificial source of lights, I notice a black snake crossing the road.
How did I get sight of the snake?

Using the clues below, what four numbers am I thinking of?

The sum of all the numbers is 31.
One number is odd.
The highest number minus the lowest number is 7.
If you subtract the middle two numbers, it equals two.
There are no duplicate numbers.

Replace the question mark with the correct number.

2 + 2= 4
3 + 3= 18
4 + 4= 48
5 + 5= ?

How many letters are in the alphabet?

What do you see in the given picture?

What is harder to catch the faster you run?

How many times do a clock's hands overlap in a day ?

Can you complete the sequence?

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

Find the next number in the series.
1 10 24 43 67 ?