## Sunday, 30 September 2012

### Math@Home: Lift – number of floors travelled

This is just for fun.....

One day I stood at the lift in 5th floor. The lift-indicator showed that the lift is at 10th floor. I wanted to go to ground floor and so I pressed the ‘down-arrow’.

Of course I always have a doubt. Which button I need to press? Especially the doubt arises when the lift is in the down floors and I need to go in the down direction. I think in this way: shall I press up-arrow such that the lift comes up to me and takes me or shall I press down-arrow as I need to go in the down direction. The whole dilemma is about which thing I need to pursue first? Pulling the lift ‘up’ to me? or the ultimate direction of my going ‘down’? The dilemma comes again when I need to go in the up-direction and the lift also stays at an upper floor.

Come back to our discussion. Luckily this time I pressed the right button. Lift arrived at 5th floor and stopped. After I got inside, it started and took me to the ground floor.

Then I asked myself, total how many floors the lift has travelled?

My thought process went like this: First, the lift travelled from 10th to 5th floor. ie., 10-5 = 5 floors. Then after taking me in, it travelled from 5th to ground, ie., 5-0 = 5 floors. So, it travelled 5+5 = 10 floors.

When I told this story to my wife, she laughed at me and said “why do you calculate in a round-about-way? lift travelled from 10th floor to ground floor. So it travelled 10-0 = 10 floors”

What has influenced me to go in a so called round-about-way?

Probably the word ‘total’. In order to find the ‘total’ number of floors, I might have brought two numbers in to picture and ‘totalled’ them.

Is this the influence of so called ‘mathematical approaches’ learnt for years?

My point here is: Applying a little commonsense and logic to math funda really blossoms the beauty of math.

#### 1 comment:

1. It made me stunned. An expert calculates every thing scientifically but a non expert without such method arrives at the answer so easily with common sense. A lay man financier calculates interest with his fingers whereas, for an educated a calculator is a must. Mokshagundam Viswesvarayya used to calculate the speed of the train by seeing his watch and counting the signal posts by sitting in a train without seeing speed-meter. K.Subrahmanyam