Atm is the urgent way of taking out the money and it is been used by many people around the world. This is one of the facility where people don’t need to stand on the long line and get their money. This machine was developed by Adrian Shephard. This has been came in practice since 1967.

John Adrian Shephard Beran the developer of this machine
To take out the money you will use one card, when you insert that card inside the machine you need to insert password which is of 4 digits. Why that password is of 4 digits, this is an interesting question. Firstly the developer Beran was purposed the 6 digits password in the ATM. But his wife developed this so he took back his decision. Carolene the wife of Beran felt very hard to remember this 6 digits and she could remember till 4 digits. So his wife asked him to keep the password of 4 digits so he kept 4 digits in a password.