What has hands, but can’t clap?

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?

If,

Akriti = 631
Levis = 521
Sroti = 521
Aneel = 533
Then,
Sunil =?

How many times can you subtract the number two from the number fifty?

When I get multiplied by any number, the sum of the figures in the product is always me. What am I?

How can you drop a raw egg from a height onto a concrete floor without cracking it?

Find the smallest sentence with all the English alphabet.

While handling a project, the landscaper is asked by the owner of the mansion that he wants four trees in front of his mansion that are exactly equidistant from each other.

How will he do it?

An evil man kidnapped someone and made them take one of two pills. One was harmless, but the other was poisonous. Whichever pill the victim took, the kidnapper took the other one. The victim took their pill with water and died. The kidnapper survived. How did the kidnapper get the harmless pill?

I’m tall when I’m young, and I’m short when I’m old. What am I?