There are two candles. Both will only burn exactly for an hour. How will you use these two candles to measure forty-five minutes?

You are given a cube that is made with the help of 10x10x10 smaller cubes summing up to a total of 1000 smaller cubes. You are asked to take off one layer of the cubes.
How many remain now?

Can you arrange four 9's and use at most 2 math symbols, to make the total 100?

A tree doubled in height each year until it reached its maximum height over the course of ten years. How many years did it take for the tree to reach half its maximum height?

What number divided by 4 is the same as that number minus 4?

A rain drop fell from one leaf to another leaf and lost 1/4th of its volume. It then fell to another leaf and lost 1/5th of the volume. It again fell on another leaf and lost 1/5th of the volume.



This process kept repeating till it fell on the last leaf losing 1/75th of its volume.



Can you calculate the total percentage of loss from the initial volume when the drop has fallen to the last leaf accurate up to two decimal places?

Can you make numbers like 24, using numbers 3,3,7 & 7 with any arithmetic operator?

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

There is one four-digit whole number n, such that the last four digits of n2 are the original number n

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.