After deciphering the mysterious letter Igor's boss received, Igor realized that before he could do anything about it, he'd better find out if the letter is real information, or meant to sabotage his work. His neighbors weren't really fond of their work, which was loud and often took place at nig...

Considering it's the beginning of a new year, I have created the following challenge. I hope to make one every month until December 2018! Here goes: Show that $AD-AB>AC^3$. Do not use scale drawings.

Each of these phrases can be reworded into 2 words, one word is another word without core (middle letter). For example "Engrave the part of geological formation" contains "carve" and "cave". The core-less word can be at the front too, The eighteen phrases which have same properties are : s...

Apparently only posting the image is not allowed. So welcome to my 2nd puzzle here. I hope this one is a little tougher.

While exploring a cave near my house, I found a small safe. Aside from some rust, it doesn’t appear to be that old. I have reason to believe there’s something valuable inside, but I don’t know the combination. There’s a poem engraved on the side that may be the key. Can you help me solve it? Thi...

Torn from my mother's breast, I have been imprisoned in a cave. Why did they do this, and what will become of me?

Here's a riddle. You will probably find this out easily :) A family lives in a cornerless cabin. The kid's mom and dad go outside. When they come back, their son is dead. The butcher said he was cutting meat. The maid said she was dusting the house. The butler claimed he was cleaning the corners...

How would you answer the brainteaser question: How many cows are there in Canada? I started by assuming: Canada population = 200 million Average Canadian consumes 500g of beef a week Average cow weight is 150 kg So the answer is (200 million * 500 g) / 150 kg = 666666 cows. ...

This is some pretty hard puzzles, I'm gonna accept the first one that is correct with all of them The Hardest Sudoku Puzzle The Hardest Logic Puzzle Three gods A, B, and C are called, in no particular order, True, False, and Random. True always speaks truly, False always speaks falsely, but ...