Find the next number in the sequence

1, 2, 6, 21, 88, __?

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

Let's play a word game. Following are some meaningless words that can be completed by adding random letters on either side of the word.

For example, the word "rdo" can be formed into "pardon".

Using the same technique, can you complete the given words?
ecalc
airb
rinci
tibac
uidel
gorit
igna
eyho

A seven-year-old kid challenged his classmates that he can make the number one disappear by adding something to it.

How can he do that?

What number when divided in half becomes zero?

If you drop a 15 kg iron bar and a 5 kg bag of cotton from a height of 50 meters which will reach the ground first?

What is the centre of gravity?

A frog is at the bottom of a 30-meter well. Each day he summons enough energy for one 3-meter leap up the well. Exhausted, he then hangs there for the rest of the day. At night, while he is asleep, he slips 2 meters backwards. How many days does it take him to escape from the well?

When I got four, I have it none.
When I got two, I have it some.
When I got none, I have it all.

What is it?

Railroad Crossing, look out for the cars. Can you spell that, without any R's ?