14 Interesting Facts of Maths - Part I.

 1. The numbers on opposite sides of a die always add up to seven.

 2. Zero is an even number.

     For some of us, this may be a "yes, I know" fact but for a lot of people, this is not something they have ever thought about.

     Each year I propose a certain set of questions to my first-year classes to get them thining, this one of them as it forces them to question their definition of what an even number is. I always get the same results, everyone in the class is willing to claim they know what an even number is but very few are willing to stand up and declare that they believe zero to be even.

      For clarity, a good definition of an even number is as follows : a number is said to be even if, when divided by 2, it remains a whole number. Zero fits this perfectly since 0/2 = 0.

 3. A useful trick for percentages. Did you know that x% of y = y% of x? 

     This can make working out percentages a much easier task. For example, try to calculate 8% of 50 in your head. Not so easy, right? Now flip it and instead work out 50% of 8, I think it's clear which is easier.

Similarly, 32% of 75 may seem difficult to calculate, 75% of 32 seems a much easier challenge.

 4. Every odd number, when written in English, contains an "e".

 5. "Four" is the only number, when written in English, whose spelling contains the same number of letters as the number itself.

 6. If you count up the number of letters in the 13 different kinds of playing cards (ace, two, three, four, five, six, seven, eight, nine, ten, jack, queen, king) you will find that there are 52 letters, exactly the number of playing cards in a deck (excluding jokers).

 7. The only number, when written in English, that is spelt with its letter in alphabetical order is 'forty". The only number, when written in English, that is spelt with its letters in reverse alphabetical order is "one".

 8. You can cut a cake into 8 equal pieces by using only 3 cuts.

     I have been told by quite a few people that this has been used as an interview question by many companies to test "out-of-the-box thinking".

     The "trick" here is to not think of a cake as a two-dimensional circle, as most people tend to, but instead as a three-dimensional cylinder, which it is. This then allows us to not only make the usual vertical cuts but we can now also make a horizontal cut. So if you use two of your cuts to form a cross on the top of the cake, effectively splitting the cake into four equal parts and use your third cut as a horizontal cut through the centre of of the cake, effectively splitting each of the four equal parts in half, you will achieve your 8 equal pieces.  

........to be continued.

Tailpiece.

Got up on the dot at 6, the chores and was ready by a half past 9. All things were tied up for our trip to Kochi, tomorrow, for our medical review.

Roy, the electrician, had come by to check and replenish the distilled water levels in the two batteries that we have.

Participated in the webinar "Self Learning and Life Long Learning - The Wheels of Success in the 21st Century" by Dr Prem Singh, IAS of the Niti Aayog from 1730 to 1830 hrs. It was nice.