what does the below math rebus puzzle mean?

If eleven plus two equals one, what does nine plus five equal?

You have to fill the below given grid in a manner that every row and column contains the digits 1 to 6. Also, make sure that the squares that are connected with each other must contains the same digit.

In a mathematical quiz, you are asked the following question:

Use three 9s in a mathematical expression without dividing or multiplying to form the number one.

Can you answer the question?

John went to buy some expensive, foreign chocolates. He only had Rs 100 with him. When he reached the shop, he got out and know that on those chocolates, there was a 15% import duty and 5% VAT.

How much worth chocolate should he buy so that he can accommodate it in Rs 100?

If it took eight men ten hours to build a wall, how long would it take four men to build it?

Cristina was born in 1888. She just had her 30th birthday today how did that happen?

I noticed one of the words in the oxford dictionary is spelled incorrectly. What about you?

10+10 and 11+11 can give you the same answer.

Explain how?

Can you think of any three-dimensional shape that comprises of exactly two surfaces?