Skip to main contentSkip to navigation

Can you solve it? The funniest jokes in maths

An Irish professor walks into a bar

UPDATE: the solutions can be read here

Photograph: DCPhoto/Alamy
Photograph: DCPhoto/Alamy

What do you call an engaged toilet on a Jumbo jet? A HYPOTENUSE!

The Theory of Relativity in a nutshell – time spent with your relatives seems longer.

Don’t knock innumeracy; my girlfriend is innumerate and we have wonderful threesomes.

These one-liners are hand-picked classics from Des MacHale, a legend in the world of mathematical humour. Emeritus professor of maths at University College, Cork, he is the author of more than 70 books, mostly of maths, puzzles and jokes.

MacHale has selected today’s puzzles, below. The first four are standard word or number conundrums, while the remaining five are lateral thinking puzzles, a MacHale speciality and a crowd-pleasing genre I feature too infrequently in this column.

Some require you to think like a novelist, conjuring up a believable situation that results in the relevant scenario. Others are misleading you by presenting a word or phrase that can be interpreted in more than one way. Take note.

1. A rich woman dies and leaves her entire fortune of two million pounds between a number of lion tamers. How much did each lion tamer receive?

2. Punctuate this sentence to reverse its meaning: A SMART DOG KNOWS ITS MASTER.

3. What is never odd or even?

4. Make this equation correct just by moving the digits about: 26 = 74.

5. Two objects perform the same task. One has many thousands of moving parts while the other has no moving parts. What are they?

6. Why did a person buy an object they didn’t want for £1 and throw it away a few minutes later?

7. Why did a man tighten the lids on all the jars in his house and put them in the fridge?

8. In a locked cabin high up on the side of a mountain, five dead bodies are found. How had they all died?

9. Why was a person standing at a bus stop with an ordinary kitchen chair in their arms?

I’ll be back at 5pm UK with the solutions. Meanwhile, NO SPOILERS! Instead, please discuss your favourite lateral thinking puzzles and post your favourite mathematical jokes.

UPDATE: The solutions can be read here

Des MacHale is an algebraist, with more than 100 academic papers in refereed journals. Yet he gained fame early in his career as a humorist. In 1976 he wrote the Book of Kerryman Jokes, which went on to sell half a million copies in Ireland.

He has written many other joke books, including a compendium of Boris Johnson jokes. His prolific output also includes four books on the English mathematician George Boole, who lived in Cork, and many books of puzzles.

MacHale’s two main interests – maths and humour – merge in his most recent book, Comic Sections Plus, an updated edition of his classic book of mathematical wit. “I would have humour lessons in all schools,” he says. “Logic and riddles are basic links between mathematics and humour; mathematics is ultra logical and humour turns logic on its head.”

His 20 books of lateral thinking puzzles are co-written with Paul Sloane. “I am hopeless at solving them but good I think at making them up,” he says. “Everybody enjoys logical thinking and being the first to get a solution.” On that note, how are you all getting on…?

Thanks to Des MacHale for today’s puzzles. You can buy his magnum opus Comic Sections Plus : the Book of Mathematical Jokes, Humour, Wit and Wisdom here.

I set a puzzle here every two weeks on a Monday. I’m always on the look-out for great puzzles. If you would like to suggest one, email me.

I’m the author of several books of puzzles, most recently the Language Lover’s Puzzle Book. I also give school talks about maths and puzzles (online and in person). If your school is interested please get in touch.