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

Find the Goldfish below the given Image.

John walks into the daily grocery shop and steals a $100 bill from the shop. An hour later John returns to the shop and buys some daily products for $40. John pays the owner the $100 bill and therefore the owner returns him $60.

How much money did the owner lose?

I travel all around the world but always stay in the corner. What am I?

Spelt forwards I’m what you do every day, spelled backwards I’m something you hate. What am I?

How many words can a quill made with the feather of a pigeon write with a 100ml bottle of black ink?

In the picture that is attached with this question, you can find a square which comprises of four little squares inside it. Consider this square to be made with matchsticks. You have to remove two matchsticks such that only two squares remain instead of five.How will you do it ?

Find out a multi-digit number that if multiplied by the number 9 or any of its multiplications products (i.e. 18, 27, 36, 45,..) will result in the multiplication factor repeated (n) number of times.

Can you find out what is missing?

1 3 5
2 4 ?

Hint: It's not six. Think out of the box.

I am taken from a mine and shut up in a wooden case, from which I am never released, and yet I am used by almost every person. What am I?