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MCAT Math Without A Calculator – Videos, Tricks and Practice

MCAT math without a calculator by Leah FischIs there Math on the MCAT? Yes.
Are you allowed to use a calculator on the MCAT?
No!

But somehow, you still need to work through multi-step calculations, including everything from decimals and exponents to trigonometry and logarithms.

And did I mention that there’s no calculator on the MCAT?

If the thought of mental math has you reconsidering your white coat dreams, let’s fix it right here.

We’ll start with the basics of addition, subtraction, multiplication and division.

Basics? Yes, but I URGE you NOT to skip it.

Instead, carefully follow along with the videos and complete the additional practice problems on the accompanying MCAT math worksheet. The worksheet includes additional practice for each video to ensure you feel comfortable with each computation before moving on.  

Download the accompanying MCAT Math Worksheet

The Basicsmcat math cheat sheet preview

Let’s start with your foundation.
Set aside 15 minutes a day for Active Writing to memorize everything on the MCAT Math Cheat Sheet. 

Wait! Did you finish your first 15 minutes of Active Writing?
Let’s continue.

How To Survive MCAT Math Without A Calculator

The MCAT is a multiple choice exam that is meant to be tough, but not so tricky as to give you answer choices that are close in value.

Round and estimate wherever you can.
There is NO point in wasting time coming up with an exact answer when the choices are quite scattered.

On the MCAT, Close Enough is Good Enough

The Introduction to MCAT Math Without A Calculator video below explains what to focus on when learning mental math and how you can get away with estimating and rounding on this exam.

Ready to learn how to solve “How many moles of Chlorine Ions are found in 4.93 L of a 0.096 molar solution?” in under 10 seconds? 

Good on the basics?
Do Now: Complete Part 1 in the accompanying MCAT Math Worksheet

Trick for Multiplying and Dividing Units of 10

Multiplication and division are much simpler when you’re dealing with units of ten (i.e. zeroes).
No zero?
MAKE ONE!
By rounding, of course.

This may be the most common trick you use in MCAT calculations as it comes up in everything from stoichiometry to conversions – from tiny to large and large to tiny units.

Ready to solve 3.47 x 1000 in less than 5 seconds?
Give it a try. Then, watch the video below before trying again.

Now, try 3.47 x 1000 again using the tricks learned above.
Do Now: Practice ‘moving the decimal’ in Part 2 of the accompanying MCAT Math Worksheet

Advanced: Moving The Decimal in Both Directions (Trick)

Now that you’re comfortable with moving the decimal to multiply and divide by factors of 10, let’s apply the same trick for more advanced practice problems, such as 0.089 x 213.

Can you do this in your head in under 10 seconds?

No obvious zeros? Estimate and round. Then, apply the ‘moving the decimal in both directions’ trick that is demonstrated in the video below.

Ready to solve 23 x 4.67 / 4.67 and 0.05 x 400 in under 10 seconds?
Do Now: Complete Part 3 in the accompanying MCAT Math Worksheet

Scientific Notation

If you jumped right to this section (I don’t blame you), I urge you to scroll back to the top and start from the beginning. 

Scientific notation and exponents in general are where things start to feel scary without a calculator. 

What to look out for:

  • Do they have the same power? 4.7 x 10^-3 + 2.3 x 10^-3 
  • Are the powers close to each other? 5 x 10^-3 + 6 x 10^-4 

Ready to learn how to solve 6.8 x 10^-7 / 5.1 x 10^-3 in your head?

Watch the Scientific Notation Without A Calculator video below.

Did you get the problem above? Ready to try a few more?
Do Now: Complete Part 4 in the accompanying MCAT Math Worksheet

Squares and Square Roots

Oh, the dreaded radical symbol.
Let’s see how to work around it so that you CAN easily solve these without a calculator.

Because YES, you can easily solve:

Radical and Exponent MCAT Math Without Calculator Leah4sci

Perhaps not 100% in your head, but let’s keep it to a few written numbers rather than wasting an entire page on your limited exam scratch paper.

See how far you get. Then, watch the squares and square roots video below to learn how to combine a few of my tricks to solve it even faster.

Ready to quickly solve (9.3 x 10-4)^2 / (2 x 10) with minimal, if any, writing?

Do Now: Complete Part 5 in the accompanying MCAT Math Worksheet

Raising Decimals To Exponents

What if those pesky exponents come back, but this time, they bring a decimal along for the ride?

For example, say you’re asked to solve: (0.3)^2
The MCAT loves these tiny numbers.
Think acid dissociation constants (using my NO ICE chart trick of course), solubility, complex force calculations and more.

Luckily, this format is just as easy to solve as whole number exponents when you quickly modify the factor of ten trick (decimal trick) above, as I demonstrate in the video below.

Just as easy, right?
Which means you can now solve (0.03)^2 and (0.05)^3 in your head without a calculator.

Let’s try a few more.
Do Now: Complete Part 6 in the accompanying MCAT Math Worksheet

Fractions, Ratios, Percentages and Proportions

When it comes to mental math, the calculation that annoys me NEARLY as much as a radical is a fraction. Fractions like to hide in many different forms, such as ratios and percentages.

Whenever possible, I try to get rid of the fraction.

For example (35 / 103) / ½. I count no less than 3 divisors. The video below will show you how to turn the above mess into this simple and easily solved expression…

Are you ready for it?
2 / 3 

Watch to see how I did it and how you can easily implement this for even more complicated questions.

Ready to easily solve this equation when r is 3 times as big, given 3 / (2r)^2 ?

Do Now: Complete Part 7 in the accompanying MCAT Math Worksheet

Trigonometry Without A Calculator

Ever feel like, just when things are starting to click, you get hit with something even more impossible? What if we agree that ONLY logs should feel that scary (if at all) and add trigonometry without a calculator to the list of ‘I got this’ math concepts? 

Perhaps you remember the old SOHCAHTOA mnemonic for sin, cos and tan.
This specifically refers to a right triangle,
A triangle that has at least one 90 degree angle, where the other 2 can be any combination of angles that add up to another 90 degrees.

Nearly all MCAT trigonometry questions will involve a right triangle or an angle that can be simplified (rounded) to a right angle.

If you struggled in pre-calc, the video below will simplify exactly what you need to know for the MCAT. Including:

  • My syn cosx trick
  • Values to memorize for sin/cos and NO there will be no rad 2 / 2 garbage
  • The graph trick so that you never mix up or forget sin/cos values again

Now that you feel comfortable with non-radical sin/cos values, solving for 9 cos 30° should be a piece of cake. Ready to try a few more?
Do Now: Complete Part 8 in the accompanying MCAT Math Worksheet

Logs and Antilogs

Logs used to scare me! Something about the non-linear mode of thinking made it difficult to comprehend, and when I don’t understand something, I tend to fear it. (You too?)

It was only when I started teaching MCAT math and when I sat down determined to finally make sense of it, that logs / antilogs finally clicked.

Instead of panicking when asked to solve Log(base4) 16 = x or Log(base15) x = 1,
Learn how to think about the problem, how to rearrange the problem, so that it becomes a simple exponents question. Exponents which you’ve already mastered above.

Log equations presented as Log(baseB) x = y can be easily rewritten as B^y = x.

The video below explains my shortcut for figuring out exactly what number goes where and WHY, to easily rewrite and think through log expressions.

Dreading logs a bit less now? Ready to conquer Log 1094357 = x and Log 0.00945 = x without writing ANYTHING down?

Do Now: Complete Part 9 in the accompanying MCAT Math Worksheet

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