All white cells must belong to exactly one island; islands must have exactly one numbered cell. Solvers will typically shade in cells they have deduced to...

Three congruent pyramids meet along a diagonal of a cube. The analogy between the decomposition of the square in the plane and the cube in space gave us a...

When you’re looking for something that will keep everyone entertained in a short amount of time, try these 221 what am I riddles and answers for kids that...

Counting the number of guesses above would give you 10, which is our answer to the maximum number of guesses to find a number between 1 and 1000. How do y...

“We could have avoided” suggests that the action is already done, and out of the way. The could-have-avoiding is over. Could have been avoided in a senten...

If the common ratio r lies between −1 to 1 , we can have the sum of an infinite geometric series. That is, the sum exits for | r |<1 . An infinite seri...

The liar would answer: NO, and the Truth-teller: YES. Without knowing which one of them is telling the truth, you won’t be able to decide. How to solve on...

Six quiz ideas that make it impossible to cheat or Google answers Guess the theme tune. Before the quiz starts, keep what’s in store a complete surprise. ...

For example, an equilateral triangle is a regular shape because all the sides are equal AND all the angles are equal. A right angle triangle is an irregul...

Love in Kleptopia. What is the number riddle?Answer: 888 + 88 + 8 + 8 + 8 = 1,000. This is the kind of number riddle you can work out with times tables, o...