Transform the word THINK into BRAIN while changing only one letter at a time in a manner that each of the word in the process is a real word!!!

How can you take 2 from 5 and leave 4?

It begins where the time ends.
Its second is an expression of surprise.
Its third is a question.
Its fourth is urinate.
It ends with a drink.

Which country it is?

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

Find the missing number in the sequence below:

Can it be possible to build a house that has all its four walls facing towards the South?

Find the next number in the series below

21 32 54 87 131 ?

No matter how little or how much you use me, you change me every month. What am I?

We have shown you a regular water barrel as below. Without using any measuring device can you check if the barrel is more than half-filled or less than half-filled?

If,

6 / 7 = 2
3 / 9 = 7
8 / 2 = 6

Then

4 / 5 = ?