How to Master MCAT Math – Without A Calculator
- Jul 23, 2018
- MCAT Blog, MCAT Prep
by Clara Gillan
“Wait, there’s no calculator allowed on the MCAT? What do I do now?” As MCAT tutors, we hear these words often, and with good reason. After all, many graduate entrance exams – such as the DAT, PCAT, and GRE – provide a simple calculator for use on at least some test sections. But this is not the case on the MCAT! No calculator is provided or allowed, so if you’re a student who typically relies on one, you might feel a vague sense of panic starting to set in. But don’t fear!
Below are 4 tips for approaching MCAT mathematics on your own, calculator-free:
1. Remember that most math on the exam will be simple
One “silver lining” of the MCAT no-calculator policy is that it forces the test-makers to design math questions that can be solved by students with pen and paper alone. Numbers will typically be fairly easy to work with – think 260 divided by 40, rather than 3071 × 29. Square roots, when you’re asked to solve them, will often be of perfect squares (16, 25, 81…) rather than “ugly numbers.” And some math is simply beyond the scope of the exam! For example, you should never have to solve a quadratic to get a question correct. So, while you can’t use a calculator, you should be able to at least muddle through the math without too much difficulty – if you’re properly prepared for it, that is.
2. When numbers are “ugly,” rounding is typically acceptable – and encouraged!
If numbers can be rounded to make math easier, this is most often a good idea. Just to be safe, though, quickly scan the answer choices before rounding your values. If the answers are extremely close together (think 1 and 1.5, or 6 × 10-3 and 5.2 × 10-3) you’ll need to be extra careful. One simple strategy is to remember whether you rounded numbers up or down. If you rounded up, the correct answer will be lower than you calculated; if you rounded down, the opposite will be true.
3. Scientific notation is your friend!
Consider the square root problem below, which certainly could be asked of you in the context of (for example) an acid-base question:
If you are familiar with your log and exponent rules, you may know that to take the square root of a value like the one above, you must square root the coefficient (6.4) and cut the exponent (-7) in half. But what is the square root of 6.4 – maybe somewhere between 2 and 3? And what do you do with “10-3.5”?
The answer is simple if we look closely. 6.4 looks awfully similar to 64, which is a nice perfect square. If we manipulate scientific notation, we find that 6.4 × 10-7 is equivalent to 64 × 10-8. Now, following the rules above gives us an answer of 8 × 10-4, and we can do this without taking much time at all. The takeaway is this: whenever you see a number that is close to something easy to work with, but is just a decimal place or two off, you can manipulate scientific notation to fit your needs. Just be careful – if you make the coefficient larger, the “10x” part of the value must become smaller.
4. Don’t sink tons of time into any single question
If you’re a student who tends to run out of time, especially in the Chemical and Physical Foundations section, you may benefit from the following rule: if a math-based question looks like it will take you longer than a minute or two, mark it, choose an answer, and move on. If you have time remaining at the end of the section, you can return to it. If you do not – well, you probably shouldn’t have been spending that valuable time on a tough math question anyway. Remember, each question is worth the same amount, so don’t let a few calculation-based problems slow you down.
Good luck – with a bit of practice, we’re sure you can ace any math problems you may see on your own exam!
Clara Gillan, is one of Next Step’s MCAT Course instructors as well as a Senior Content Developer. She has years of experience working with the MCAT and the students who take it, giving her an intimate knowledge of the exam.
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