Replace the question mark with the correct number.

What will be the best approach to finding all the prime numbers less than 75 that leave an odd reminder when we divide them with 5?

What is the difference between a jeweller and a jailer?

Can you replace the X (both small and big x) with the numbers between 1 to 19 such that all the rows of 3 numbers between X (big x) sum to 23?

By moving exactly three matchsticks can you make the below equation true.It can be solved by 3 ways.

I inserted a coin in a bottle and closed its mouth with the help of a cork. Now, I was able to take the coin out from the bottle without taking out the cork or breaking the bottle. Can you tell me how I did it?

As shown in the image, the nine Dogs are square fenced. By constructing just two square fences can you make sure that two Dogs cannot meet each other without crossing the fence?

Most people think of me as money. But when they find me in the water, they won’t get any money out of me. What am I?

If you had a pizza with crust thickness 'a' and radius 'z', what's the volume of the pizza?

What does below pictogram mean?