Cut A Bagel Into Two Linked Halves

For those of you who don’t know what a bagel is, it’s a bun with a hole in the middle. A doughnut made out of bread dough. If you can’t get hold of a bagel for the puzzle on this page, use a doughnut instead.

The Mouse-Eating Geniuses of Bihar

The Mushar people are amongst the poorest of the world’s poor. If you search the web, you’ll find descriptions of these people that range from encyclopaedic to heartbreaking. Their problem is not just that they are poor. They also live in the poorest state in India. Worst of all, they are considered “untouchables” in the Hindu caste system.

Orchard Puzzle

I recently received a tough puzzle as a gift from my brother. The name of the puzzle is “Orchard”, and so far, indeed, it seems quite tough! The first step in solving it is to solve this puzzle :

Three Sons, Eleven Horses

Here’s an old fraction puzzle. I have no idea who invented this, or whether it is decades or centuries old, but it’s always been a favorite conundrum of mine.

It starts with a man who wills his possessions to his three sons. The will specifies that the eldest son should get half his fortune, the second son a quarter, and the youngest son a sixth.

Pythagoras Jigsaw Puzzles

“Everyone” knows that 3×3 + 4×4 = 5×5. This little factoid, and other Pythagorean triplets, can be the basis of a nice set of puzzles. Here’s the first. If you draw a 5×5 square on graph paper, how can you cut it up (following the lines on the graph paper) so that the pieces can be rearranged to form a 3×3 square and a 4×4 square?

This is not so hard to do. Here’s one possible solution :

Perimeter, Area and Volume

How long and wide must a rectangle be, for its area to equal its perimeter? Assume the width and length are whole numbers.

This is a nice little puzzle to let younger kids explore – if they find the puzzle as interesting or frustrating as I expect, they’ll remember the formulae for perimeter and area for the rest of their lives. For older kids, a bit of algebra gives the answer quickly.

A Little Conundrum

Consider the sentence :

“Thsi sentence hsa three errors.”

The puzzle is to find the errors. Two of them are easy to find :

• “Thsi” should read “This”,
• “hsa” should read “has”,

but where’s the third error?

Coconuts and Diamonds

One of my favourite puzzles of all times is a bit tough for a typical lower-school kid. It goes like this :

Five men and a monkey are stranded on a desert island. They spend the day searching for food, and by evening, they have collected a big pile of coconuts. Too tired to do anything but sleep, they agree to share the coconuts out in the morning.

However, one of the men wakes up just before midnight. He doesn’t trust his companions, so he goes to the pile of coconuts to take his share. he divides the coconuts into five equal piles, with one left over. He takes his share and hides it, gives the spare coconut to the monkey, collects the rest back into a pile, and goes back to sleep. Continue reading Coconuts and Diamonds

Pumpkin Puzzle

We have some pumpkin plants growing in our yard. I counted them at one point, and there were 24 plants. This inspired a little puzzle –

If I have 24 pumpkin plants, and half of them grow a pumpkin, and half of those that grow a pumpkin grow another, and half of those that grow another grow yet another still – then how many pumpkins do I get in the end? Continue reading Pumpkin Puzzle