Welcome here and try to solve some cool math problems...

Problem 1

Imagine yourself alone on a little island deep in the ocean. And not far away you can see a big submarine moving to the East. The wind speed is about 20 miles per hour and it's blowing to the south, the temperature of air is 86F (30C), it is 12.00 am. In what direction the submarine's smoke moving?

Problem 2

Try to answer the following expression.

Problem 3

So much strange signs on the blackboard... Try to name some of these signs.

Problem 4

This problem is VERY hard. Show it to your parents and all your friends. Maybe together you will be able to solve it... So, imagine that you've found ten bags of gold coins. And you know that there is one bag with false coins. The weight of real gold coin is 1 gr, the weight of false coin is 1,1 gr. How can you determine which bag has false coins by measuring the weight, if you can to measure coins only one time?