How to Study

Mastering Multiple-Choice Math
If you can avoid a calculation, it will save you time. For example, 
figure out the answer to the following problem without actually 
doing the math:
281 
⫻ 243 ⫽
(A) 53,762
(B) 113,428
(C) 67,283
(D) 489,593
How to Study
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By performing one simple task, you can eliminate two of the possible
answers. Multiply the last digits in each number (1 
⫻ 3). The answer
must end in 3. So (A) and (B) have been eliminated...that fast!
Now, eyeball (C) and (D). Can you find the right answer quickly? 
Here you are doing educated guessing, known in math circles as
“guesstimating.” Look: 281 
⫻ 100 is 28,100. You should be able to 
do that without any tools. Therefore, (D) has to be wrong. You are
left with (C).
Should you do the actual math to double-check your answer? 
I wouldn’t. You are certain that (A) and (B) are wrong. Absolutely.
You know that (D) is much too high. Mark (C) as the answer and
move on.
Here are other ways to better your score on math tests:
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Try to figure out what is being asked, what principles are
involved, what information is important, and what’s not. Don’t
let extraneous data throw you off track. Make sure you know
the kind of answer you’re seeking: Is it a speed, weight, angle,
exponent, square root? 
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Whenever you can, “translate” formulas and numbers into
words. Estimate the answer before you even begin the actual
calculation. At least you’ll know the size of the ballpark you’re
playing in! 
■
Even if you’re not particularly visual, pictures can often help.
Try translating a particularly vexing math problem into a 
drawing or diagram. 
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Play around. There are often different paths to the same 
solution, or even equally valid solutions. 
■
When you are checking your calculations, try working 
backwards. I’ve found it an easier way to catch simple 
arithmetical errors. 
Chapter 8
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How to Study for Tests
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Try to write down all of your calculations—neatly. You’ll be
less likely to make a mistake if you take your time, and if you
do make a mistake, it will be a lot easier to spot. 
■
Show every step and formula, even if you would normally 
skip a few. If you knew all of the principles and formulas but
miscalculated near the very beginning of your analysis, you 
are not going to arrive at the correct answer. But many
enlightened math teachers will penalize you very little if 
they can clearly see you knew your stuff and managed to 
do everything right, with the exception of hitting the right 
button on your calculator. 
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And if you are using a calculator, double-check your answer
immediately. The chances of hitting a wrong number are high;
the chances of hitting the same wrong number a second time
are not.