 # Articles

## Mathematics by Jannat

Ubiquity, Volume 2008 Issue June | BY Jannat Jannat |

Full citation in the ACM Digital Library Arrgh!!! Well! If this is your reaction upon hearing the word MATH, you are not alone. You too are part of that ever increasing family which loves to hate it.

Arrgh!!!

Well! If this is your reaction upon hearing the word "MATH", you are not alone. You too are part of that ever increasing family which loves to hate it.

I'd like to quote Thomas Friedman - The World Is Flat. It indeed is. (And Oh, I don't want to offend the geography and science people.) We are all on a level playing field when it comes to Math. It has always been the pet-peeve of most of us.

Do you still remember the stories in the Reader where the valiant hero fights with the tiger? Interesting, weren't they? The only difference (though a major one) between Math and the other subjects is that Math is not a spectator sport. You need to jump into the arena and face the tiger yourself. (Thank God, you don't take things literally in Math!)

But you can afford to forget the fairytales, not Math. Ranging from algebra to probability, all of it is needed at some point in time. Ok, I agree you don't need binomial equation to arrive at the expenses of your groceries, but you certainly need a little bit of arithmetic.

But how wonderful it would be when you utter out the results of lengthy calculations even before your friend who is busy punching numbers in the calculator.

Let's try to put in words (rather numbers) what I am talking about. Can we find out how much is 35 x 45? Sure, we can! Or else what are calculators made up for? But here I meant can we mentally find out the answer.

So, give it a try. Are you reaching out for the calculator? In case you are, then let me tell you. There's no need, really. Take my word. But how to find the answer in a jiffy?

If you ever have to multiply two numbers ending in 5 that are at a difference of 10 from each other, use this simple trick.

Multiply the ten's digit of one number with 1 added to ten's digit of the second number. Sounds all Greek? Let me explain.

In 35 x 45, take 3 (ten's digit of first number) and 1 + 4 (ten's digit of the second number) and multiply them.

We get

3 x [ 1 + 4 ] = 3 x 5 = 15

These become the first two digits of your answer. To arrive at the last two digits, just write 75 at the end.

So you get 1575 as the answer!

And now you can rush to grab your calculator and verify it.
Checked? Stupefied? Yes, it indeed is the right answer and it always works.

Let's take up another example

65 x 75 = ?

Using the same trick,

6 x [ 1 + 7 ] = 6 x 8 = 48

Writing 75 at the end of it, we get 4875 and that's what you get after multiplying 65 and 75!

Not mere arithmetic calculations, (algebra, geometry, trigonometry etc included) Math is fun. The only requirement is to learn and practice it the right way. Math is not at all a draconian subject; it just needs to be treated well.

Learning the new and simpler way will turn that awful "Arrgh" into the "Aha" moment.