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

If your uncle’s sister is not your aunt, what relation is she to you?

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?

Chef Andrea has to light the kitchen stoves to open her restaurant for the day. There are three stoves in the kitchen: A glass stove, a brick stove, and a wood stove. She only has one match. Which does she light up first?

What is the next number in this series?

4,12,84,3612....

Use only one mathematical symbol and all numbers (0-9) to get a sum of 99

Below the four parts have been reorganised. The four partitions are exactly the same in both arrangements. Why is there a hole?

No matter how little or how much you use me, you change me every month. What am I?

An exterior architect is asked by a builder to plant seven trees in a manner that there are exactly six rows of trees in a straight line and each row has three trees in particular.

How will he do it?

Why is Saturday stronger than Monday?