# Arithmetic TRICKS

Discussion in 'MCAT Discussions' started by VandyDerm, Jun 1, 2008.

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1. ### VandyDerm Banned

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Hey Guys,

I was wondering what ARITHMETIC tricks you could implement int he MCAT...im just confused because there are a lot (ignoring the ones in EK), but I need to know if you have a list compiled after extensive practice that you would recommend knowing.

3. ### SN2ed Moderator Emeritus

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Rounding, no seriously rounding really helps.

4. ### StarStup

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I seriously went to the library and checked out a 5th grade text book. It has lots of stuff on unit conversions, rounding, fractions, and exponentials. I felt stupid doing problems out of it...but it helps you to do them fast and gives you practice. I hate how I've was so dependent on calculators! I couldn't even add fractions without the calculator until I looked at the text book. Just practice problems because you don't want to spend a lot of time on them on the test or to make stupid math errors. Good luck!

5. ### BerkReviewTeach Company Rep & Bad Singer Exhibitor

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I so 100% agree with your comment. It's funny you mention fifth grade, because we have one two-hour class dedicated to nothing but solving math questions and for nearly every answer explanation, we discuss the highly advanced method of having no shame and doing it like a fifth grader.

Key things that I have found hurt people are:

Powers of ten: This is helped by decimal hopping and labeling numbers with "increased by factor of 10" or "decreased by factor of 100". It comes down to paying attention really.

Ratios: These are made easiest by making denominators easy to deal with. Also, if a ratio is hard to calculate as written, flip it and see if it is easier the other way. We somehow emotionally deal with bigger-over-smaller ratios better than smaller-over-bigger ratios.

Fractions and Equivalent Decimal-based Value: Learn the correlation between fractions and decimals 1/4 = .25, 1/5 = .2, etc... These can prove EXTREMELY useful on the exam.

There are many more strategies and techniques, but these are generally the big three for most people. A little practice goes a long, long way.

The funny thing I've found is that the supposedly more difficult math skills like logs, square roots of complex numbers, and exponential decay/growth are typically easier for people than basic division, fractions, and multiplication.

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Learn how to estimate log calculations:

-log (1E-5) = pH 5
-log (1E-4) = pH 4

And -log(3E-5) =~ pH 4.5

If you remember that a '3' in front of the 10^-X, corresponds to the halfway point between two pH values then you can estimate whether all H+ (or OH-) concentration values will give a pH between X and X.5, X.5 or X+1, etc...

7. ### VandyDerm Banned

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What textbook or SAT-like book could I use that would get these fundamentals into becoming a second language. I love ur advice Vihsdas, and its little bitty tricks like those I was wondering if you had a list of after taking the MCAT, I am pretty sure u may have had like 20-30 tricks in ur bag to tackle physics problems...other than that I really need book titles to do in a couple of days.

thanks

8. ### gogopogo Canadian stereotype, eh?

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Wow, what a great little tidbit! Thanks much for this stuff!
"My log has a magic number. It's three."
A silly way to put it, but instantly memorable.

9. ### secretin11 Banned

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Do you own the company or something? you don't lose a beat do you?

10. ### gogopogo Canadian stereotype, eh?

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Oh snap!

jk I actually do really appreciate the advice I've seen BerkReviewTeach give on many threads, shortcuts and the such.

11. ### secretin11 Banned

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Hey BerkRewTeach how old are you? I am convinced you must either own that company or you must get a big share of the company's profit, or maybe you work for them and your 9 to 5 job consist of getting on pre-med websites and getting pre-meds to sign up for the course. Which one is it? please be honest? I went through some of your post and at every chance you get its BR BR BR over and over. which one do you think it is gogopogo? great name by the way.

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Last edited: Jun 1, 2008
12. ### yousafob

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One of my favorite tricks is Left Add Right Subtract. This refers to exponents, for example, if you move the decimal point to the left one, you need to add one to the exponent. If you move the decimal point to the right one, you need to subtract one from the exponent.

1 x 10^5, move left one decimal point to the left and you got .1 x 10^6

I hope this helps.

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I have a better idea. Use the search function and find the answer by yourself (since BRT doesn't keep it a secret in the slightest, nor does he have any reason to) and keep your posts on topic and don't derail the thread.

Thanks. Back to your regularly scheduled topic: "Arthimetic Tricks".

14. ### secretin11 Banned

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common, that's no fun. Why don't we let the man speak for himself. hunh BRT? and you why do I sense some hostility? who are you? I wasn't addressing you really, I am just curious and blunt. If no one will say it I will. I just simply say it like it is. and by the way since you are a moderator, can you get what up doc to change is avatar? it disturbs me.

15. ### BerkReviewTeach Company Rep & Bad Singer Exhibitor

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Early 30s, neither, and okay.

PMs work better for this sort of thing than hijacking a thread. But I guess it has been derailed. So, with apologies to the OP and a promise to start this thread up again given that this one has deteriorated, let me field your inquiry.

First off, I am a seasoned part-time employee of BR. I love my job and have an emotional interest in the company, because I know the owners well. If you knew anything about the small company we are, you'd realize that it's tight-knit. I can't speak for every teacher, but I'm pretty sure most would agree that the autonomy and low-stress teaching is the best part of working here. We take pride in fighting the corporate giants. If I'm guilty of flag-waving, and perhaps I am, it's no doubt rooted in an underdog feeling. I'm competitive to a fault and while you are off target in suspecting that money is a driving force, I definitely think highly of the course. Their is an intense drive to have our students kick butt on the exam over students from other programs. Every time someone comes back with a great score, it's an amazing feeling of pride. So you'd have to say that I definitely feel like a part of the company fabric. Although it's only a small part, I helped develop and edit some of the materials and worked on curriculum. Enough so that I take comments about them to heart.

As for me, I was a pre-med originally, but reached a realization that I didn't really have the drive to pursue medical school. I started tutoring part time and have kept a hand in it most sessions while working full-time elsewhere. My real job is rather mind-numbing, so this is a great way to keep a hand in teaching. The selling point they told me when I first started was that you get to teach smart students and there's no grading and thus no whining about grades. It's purely about learning. It's the perfect part-time job. I get to teach a little here and there and they let me do some of the other things if I want.

So while I respect cynicism in general, I have to admit being a bit taken back by your attack. I''m not sure what you have to gain personally from your questions, but I'm sure you have your reasons. And for what it's worth, I sincerely hope you do not take our course. The amazing thing I've found is that for the most part, nearly everyone in our class has a great heart and their pursuit of medicine is driven by a call to serve and help others. It's an honor to be around them. From what I can tell in your post, you would not fit that description, so it wouldn't be a good fit for you.

I sincerely apologize to anyone posting for math tricks. Hopefully this thread will die off to another page and the new oen will pick up where this left off.

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Last edited: Jun 2, 2008