How can you make number one disappear by adding something to it?
The person who makes it has no need for it; the person who buys it has no use for it. The person who uses it can neither see nor feel it. What is it?
Is the statement valid that it does not matter how much older a sibling is, eventually the younger one will be half as old as the older one?
What has many keys but can’t open a single lock?
There is a box full of marbles, all but two are blue, all but two are green, and all but two are red. How many marbles are in the box?
Can you solve the tricky chess rebus puzzle below by ciphering the hidden meaning?
On my way to St. Ives I saw a man with 7 wives. Each wife had 7 sacks. Each sack had 7 cats. Each cat had 7 kittens. Kittens, cats, sacks, wives. How many were going to St. Ives?
Can you find the next number in the below sequence 3 , 7 , 10 , 11 , 12 , 17 ?
A man dies of old age on his 25 birthday. How is this possible?
Double it and multiply it by 4. Then divide it by 8 and you’ll have it once more. What number is it?
A prisoner is told: "If you tell a lie, we will hang you and if you tell the truth, we will shoot you." What did the prisoner say to save himself?
There is a cryptic organization called Cicada 3301 that posts challenging puzzles online, possibly to recruit codebreakers and linguists.