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 is the largest amount of money that you can possess in change and still if someone asks you for a dollar, you won't be able to give?

How can you make number one disappear by adding something to it?

What has many keys but can’t open a single lock?

A river should be crossed by a father, a mother and their two sons and two daughters.
There are some rules that should be followed while crossing the river. There can be only two people in the raft while crossing. The daughters cannot be with their father unless there is the presence of the mother. The sons cannot be with their mothers unless the father is present. Unless the guard is on the board, the criminals cannot be with any of the family members. Only the adults like the father, the guard, and the mother knows to use the raft.

How will they cross the river?

In a supermarket, there is an intelligent glass pane before a refrigerating unit. This glass pane allows cherries and apples through it but does not allow grapes and Orange to pass through it.

Can you identify the rule that the glass pane is following?

Find the hidden panda in the image below.

There are 20 people in an empty, square room. Each person has full sight of the entire room and everyone in it without turning his head or body, or moving in any way (other than the eyes). Where can you place an apple so that all but one person can see it?

Count the squares in the matchstick puzzle below?

What seven-letter word has hundreds of letters in it?