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!!!

I have 50 feet long of cloth, I need to create 50 handkerchiefs each size of 1 foot. I take one minute to cut a 1-foot handkerchief. So how long will it take to cut 50 handkerchiefs?

You have a three-gallon and a five-gallon measuring device. You wish to measure out four gallons.

You are given a cube that is made with the help of 10x10x10 smaller cubes summing up to a total of 1000 smaller cubes. You are asked to take off one layer of the cubes.
How many remain now?

I am a seven-letter word but if you remove four of my letters I will have one left. What word am I?

What does the following represent?

N N N N N N N

A A A A A A A

C C C C C C C

I am the beginning of the end, and the end of time and space. I am essential to creation, and I surround every place. What am I?

A Shopkeeper sold a few chickens to four different customers on a particular day. It was such that each customer purchased half of the remaining chickens and half the chicken more.

Can you find out how many chicken were sold by the shopkeeper on that day if we tell you that the fourth customer bought a single chicken ?

Can you count the number of squares in the figure below?

What is always in front of you but can’t be seen?