Math & Number Riddles

Five hundred begins it, five hundred ends it, Five in the middle is seen; First of all figures, the first of all letters, Take up their stations between. Join a...

There is a party of 100 high-powered politicians. All of them are either honest or liars. You walk in knowing two things: - At least one of them is honest. - I...

Three people check into a room. The bill is $30. They split it 3 ways. Later on the hotel realizes they should have charged $25 so they send a bellhop to return...

Two is company and 3 is a crowd. What is 4 and 5?

What number do you get when you multiply all of the numbers on a telephone's number pad?

There is a chain nailed to the wall. The chain is 10 feet long and the centre of the chain dips down 5 feet from where each side of the chain is nailed to the w...

If it takes 5 machines 5 minutes to make 5 widgets, how long would it take 100 machines to make 100 widgets?

In a bicycle race, the man who came two places in front of the last man finished one ahead of the man who came fifth. How many contestants were there?

A child playing on the beach had 6-1/6 sand piles in one place and 3-1/3 in another. If he put them together, how many sand piles would he have?

When is 1500 plus 20 and 1600 minus 40 the same thing?

What is the largest possible number you can write using only 2 numbers - just 2 numbers, no other mathematical symbols?

If you toss a coin 10 times and it lands heads up every time, what are the chances it will land heads up if you toss it again?

An interesting formula for generating a good many (but not all) primes is n2 + n + 41. If we plug in consecutive integers 1, 2, 3, etc., at least up to a certai...

100 passengers are boarding a plane with 100 seats. The first passenger in line has lost his boarding pass and chooses a random seat to sit in. Each subsequent...

When I take five and add six, I get eleven, but when I take six and add seven, I get one. What am I?

There are 25 red balls, 47 green balls and 3 blue balls in a basket. There is a blind man. What is the minimum number of balls that the blind man has to pick to...

A basket contains 5 apples. Do you know how to divide them among 5 kids so that each one has an apple and one apple stays in the basket?

In a lake, there is a patch of lily pads. Every day, the patch doubles in size. If it takes 48 days for the patch to cover the entire lake, how long would it ta...

If Mr. Flynn is 90 centimeters plus half his height, how tall is he?

One brick is one kilogram and half a brick heavy. What is the weight of one brick?