Category Archives: Fun with Mathematics

Household chores for mathematicians!!! :-)

Thanks to Evelyn Lamb and Scientific American. πŸ™‚

The infinite hotel paradox : due Jeff Dekofsky

This hardcore stuff about “infinity” , quite nicely, explained was pointed out to me by my ISC XII student, Mr. Utkarsh Malhotra! πŸ™‚


A test about tests!

“We had to answer all the questions, just “Yes” or “No”.” Fran explained. “The first paper I got only five wrong.”

Ben smiled. “That sounds good. What about the other paper?”

“Tough, but the same number of questions,” the girl replied. “I got just a third of them wrong, so over all I got 75 percent right for the two papers.”

How many questions in each paper?


Nalin Pithwa.

Daddy knows best!

“It’s only teenage infatuation,” Tom declared. “I do like Bob, but he is double your age.”

“Come on, Dad, that’s nothing these days,” Cathy replied. “He doesn’t look it, and anyway three years ago the digits of my age added up to the same as the digits of his age did.”

What they call aΒ non-sequitur?Β How old was she?

Reference: Entertaining Mathematical Teasers, and how to solve them by J.A.H. Hunter, Dover Publications Inc., New York,Β available at Amazon India.


Nalin Pithwa.


Awesome inspiration for Mathematics !

Fun with Math websites: MAA

cheers to MAA! πŸ™‚

Nalin Pithwa.

Frenchmen and mathematics ! :-) :-) :-)

Mathematicians are like Frenchmen: whatever you tell to them they translate in their own language and forthwith it is something entirely different. — GOETHE.

πŸ™‚ πŸ™‚ πŸ™‚

Three in a row !!!

If my first were a 4,

And, my second were a 3,

What I am would be double,

The number you’d see.

For I’m only three digits,

Just three in a row,

So what must I be?

Don’t say you don’t know!


Nalin Pithwa.

Three More Quickies


“Professor Stewart’s Cabinet of Mathematical Curiosities”, Ian Stewart.


  1. If five dogs dig fiveΒ holes in five days, how long does it take ten dogs to dig ten holes? Assume that they all dig at the same rate all the time and all holes are the same size.
  2. A woman bought a parrot in a pet shop. The shop assistant, who always told the truth said, “I guarantee that this parrot will repeat every word it hears.” A week later, the woman took the parrot back, complaining that it hadn’t spoken a single word. “Did anyone talk to it?” asked the suspicious assistant. “Oh, yes.”. What is the explanation?
  3. The planet Nff-Pff in the Anathema Galaxy is inhabited by precisely two sentient beings, Nff and Pff. Nff lives on a large continent, in the middle of which is an enormous lake. Pff lives on an island in the middle of the lake. Neither Nff nor Pff can swim, fly or teleport: their only form of transport is to walk on dry land. Yet, each morning, one walks to the other’s house for breakfast. Explain.

Shared by Nalin Pithwa.

The animals went in which way

The animals may have gone into Noah’s Ark two by two, but in which order did they go in? Given the following sentence (yes, sentence! — I make no apologies for the punctuation), what was the order in which the animals entered the Ark?

The monkeys went in before the sheep, swans, chickens, peacocks, geese, penguins and spiders, but went in after the horses, badgers, squirrels and tigers, the latter of which went in before the horses, the penguins, the rabbits, the pigs, the donkeys, the snakes and the mice, but the mice went before the leopards, the leopards before the squirrels, the squirrels before the chickens, the chickens before the penguins, spiders, sheep, geese and the peacocks, the peacocks before the geese and the penguins, the penguins before the spiders and after the geese and the horses, the horses before the donkeys, the chickens and the leopards, the leopards after the foxes and the ducks, the ducks before the goats, swans, doves, foxes and badgers before the chickens, horses, squirrels and swans and after the lions, tigers, foxes, squirrels and ducks, the ducks after the lions, elephants, rabbits and otters, the otters before the elephants, tigers, chickens and beavers, the beavers after the elephants, the elephants before the lions, the lions before the tigers, the sheep before the peacocks, the swans before the chickens, the pigs before the snakes, the snakes before the foxes, the pigs after the rabbits, goats, tigers and doves, the doves before the chickens, horses, goats, donkeys and snakes, the snakes after the goats, and the donkeys before the mice and the squirrels.

πŸ™‚ πŸ™‚ πŸ™‚

Nalin Pithwa.