Question

Dear Mitch,

I know everybody's been sending in questions begging for tricks or techniques for the SAT, and I am one of them. Is it true that there are some questions that a calculator will always get wrong? (My Sister saw an interview with you a couple of years ago, and she said that you said that about calculators) So is that really true, and if it is, how do you know when you see that kind of problem?

Sincerely,

Greggory G.

Oceanside, New York

Answer

Dear Gregory,

Yes, that is true. However, while that seems like 'bad news' to a lot of students who really get thrilled that the rules of some tests permit the use of calculators, there is a 'good news' side to it as well, which has two parts.

__PART I of the good news__: The problems on these tests desiged to catch the students who rely too heavily on their claulator are VERY EASY to spot.

__PART II of the good news__: These problems, once spotted, are almost always extremely easy to do without a calculator!

Think about this: Calculators have a finite number of spaces for digits, so if a long decimal, for example, goes on and on for a few hundred places AFTER the limited number of digit spaces on the screen ends, then, obviously, the calculator has to 'round'.

That is usually fine. However, there are many, many simple-looking fractions which, in decimal form, will go on and on forever. EXAMPLE: 1/3 on the screen of a calculator is typically this: .333333333333333333333333333... until the screen is filled.

And 2/3 is typically this: .666666666666666666666 until, well, you know.

So if there is a question that uses only fractions like those, DO THE PROBLEM WITH A PENCIL IN FRACTIONAL FORM. IT IS EASY TO DO, AND THERE IS NO REASON TO BE AFRAID.

HOWEVER, THERE** IS **REASON TO BE AFRAID OF TRUSTING YOUR CALCULATOR TO DO IT IN A DECIMAL CONVERSION: WITH SUCH AN EASY FRACTIONAL QUESTION, LETTING THE MACHINE ROUND MANY DIFFERENT NUMBERS THAT WILL GET MULTIPLIED TOGETHER IS A MORONIC APPROACH.

*MORONIC.*

WHY? Because the rounded answer your screen will present at the end is rounded. It is not exact. HOWEVER, YOU CAN BET THAT THAT WRONG ANSWER WILL BE AMONG THE ANSWER CHOICES THE TEST WRITERS WILL OFFER.

DON'T BE A MORON. DON'T FILL IN THAT OVAL WITH THE NUMBER TWO PENCIL YOUR MOTHER BOUGHT YOU.

WHY???

BECAUSE IT IS WRONG!!!!!!!!!!!!!!!!!!!!!!!!!!!!

WRONG.

DO IT YOURSELF! PUT THE CALCULATOR DOWN!

I PROMISE YOU IT WILL STILL BE WAITING FOR YOU WHEN YOU CLUTCH IT AGAIN FOR THE NEXT PROBLEM. DON'T WORRY, IT WILL STILL BE THERE TO OFFER THE HELP AND LOVE THAT YOU'VE COME TO EXPECT FROM IT. BUT KNOW WHEN TO SAY NO. AND DON'T LET NERVOUSNESS TURN YOU INTO A MORON.

Hope that helps,

Mitch