Thursday, May 22, 2014

9-5+5*0+3 simple Bodmas Illusion!!

I call this problem of 9-5+5*0+3 as a simple Bodmas Illusion!!

Like asking a grown up to recite nursery rhymes will cause him liitle efforts. But its not that he cannot do so or he has grown lesser in knowledge. It's just you forgot because you are not doing that often. And, then comes perception. Ideas on which you have not worked recently, and have only heard buzz words, will be not in much terms with you - Even if you believe you know it well. That's perception or simply I-Know-That-Stuff-Well syndrome. For instance just ask yourself how well you know about Big data or NLP or AWS or even cloud computing in that sense. Lol ;)

In the similar vein, I post you a simple puzzle today. What do you feel is answer to :

9 - 5 + 5 x 0 + 3 = ?


I myself posed this question over my WhatsApp group and found many giving correct answer. But I was amazed by many who gave wrong. Here, I am not talking about some completely vague answers like 0, 10 and 90. You won't imagine, I even had these responses. Yes! That's true!!


In any case, the most preferred answers were 1 and 7. To your surprise, 1 received the largest share of vote. However, the correct answer is 7.

People who came with 1 as answer did following:
Equation: 9-5+5x0+3=...? I believe the answer is 1, is that correct?
5x0=0
5+3=8
9-8=1

And, yes the keyword that they stood by was BODMAS Rule.


However, the correct answer being 7, needs other explanation. And, in any sense it should not violate Bodmas as well. You know its hard to shun whatever you learnt in childhood. God! Why don't we learn to love and love and love...

Anyways, the workflow for the correct answer is as follows;
5*0 is 0
So it becomes, 9-5+0+3
ie. 9-5+3
In algebra what we follow, we do arithmetic by the rule of BODMAS. But here, by bodmas it does not mean 9-(5+3). So, 1.
No, No. 1 is wrong answer. Because what we assumed here is an imaginary bracket, which never existed. Look, now you must have started feeling why the post is termed to be as Bodmas Illusion!!

In algebraic calculations and closed group mathematics which the world follows, we practice Right to left arithmetic. So even if you add first, it is -5+3 which is -2. At last 9-2 gives 7.

Or simply, 9-5+3 by right to left gives 4+3 hence 7.

Had the puzzle been so simple, it would have not come in my post. You can even type "9-5+5*0+3" on Google to see what it calculates.

Voila!!
Someone has learnt Bodmas again!!
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