Friday, March 16, 2018

Mathemagic Puzzle

Arun was being his usual boastful self – bragging on and on about everything that he could do. “Do you know what is 17 squared – 16 squared?”
Everyone looked at him.
“Ha ha! Knew you didn’t! 33!” he gloated.
“I bet you memorised that all night only to impress us in the morning!” Nirvaan said.
“Really? Ask me the difference between the squares of any 2 numbers next to each other, any 2, and I will tell you in less than a minute.”
Ishaan, Vedant, Neel and everyone else took turns testing him, but he always came out on top.
How was Arun doing this?


Buy contact lenses said...

Amazing blog and very interesting stuff you got here! I definitely learned a lot from reading through some of your earlier posts as well and decided to drop a comment on this one!

Z said...

Add together each number and add that to the lower one - that is 13 squared is 169, add 13, add 14, it's 196 which is 14 squared. Or 4 squared is 16, add 4, add 5, that's 25 which is 5 squared.

When I want to distract myself from what the dentist is doing to me, I do mental arithmetic and times tables. My favourite is the 17 times table, but I can't tell you why, because I don't know!

How do we know said...

Dear Z: :) Yes, that is the right answer. He was just adding the 2 numbers! :)

I totally understand 17 being your favourite table. Mine is 72, and even I don't know why!