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Can You Use a Calculator on the GMAT?

Are you allowed to use a calculator on the GMAT?  Are calculators of any kind permitted on the GMAT?

No. The only exception where you can use a calculator on the GMAT: the new Integrated Reasoning section.

 

I always use a calculator for math: should I panic about no calculator on the GMAT?

No!  Not at all!

First of all, the fact that no calculator is allowed places significant limits on the authors of the GMAT – they can only ask a question which could reasonably be answered without a calculator.  That saves you from having to know a whole slew of more advanced math, because they simply can’t put it on the GMAT.

Furthermore, there are some key study strategies you can implement now that will prepare you well for your no-calculator-day when you take the real GMAT.

 

Tip #1: Practice Mental Arithmetic Daily

If you were going to run a marathon six months from now, it would be a spectacularly bad idea to plan not to do any running or jogging until the day of the race.  Much like your physical muscular system, your “mental arithmetic muscles” need to be worked out and in shape for the day of the test.

Of course, of course, do all your GMAT math practice questions without a calculator.  But beyond that, find little ways to do arithmetic every day.  Add up the total of your grocery order to the nearest dime while you are standing in line.  When you are driving at a certain speed, calculate how far you would drive in, say, 45 minutes at that speed.  You can even enlist a friend, spouse, or teenage child to hold a calculator and check your results.  If you do zero mental math, you will be rusty at first – it will be like jogging for the first time ever.  Trust that as you practice, you will acclimate.

By the way, mental math skills will always be important in the business world: wherever there’s money, there’s numbers!

 

Tip #2: Estimation without a calculator

You do not need to figure out an exact answer for every math question on the GMAT: often, estimation is enough.  If you see 48.9 x 8.11, you know that’s going to be very close to 50 x 8 = 400, and that may be close enough to isolate an answer on problem solving.  See the practice questions at the end for a demonstration! For more estimation-without-a-calculator strategies, read The Power of Estimation for GMAT Quant.

 

Tip #3: Cancel BEFORE you multiply

This is a huge one, and nobody seems to talk about this.  If you internalize this habit, you will simply remove one of the biggest potential stumbling blocks on GMAT math.

Suppose, in the course of a GMAT math problem, you have to solve the following proportion for x:

56/x = 24/27

Of course, the first step will be to cross-multiply:

56*27 = 24x

At this point in the problem, an unstrategic GMAT taker would make the disastrously bad move of finding the product of 56 x 27 (the answer is over 1000).  That’s the absolute last thing we want.  Unless someone comes into the GMAT with a gun and forces you at gunpoint to find the product of two numbers, do not do so.

You see, the next step will be to divide by 24, to isolate x. Dividing by 24, we have

x = {56*27}/24

and at this point, we are in a perfect configuration to cancel.  We can cancel a factor of 3 from both 27 and 24, leaving 9 and 8 respectively.

x = {56*9}/8

Now, we notice that 8 divides evenly into 56 right{56/8}=7

x = 7*9 = 63

Notice, instead of multiplying first, multiplying 2 two-digit numbers to get an unwieldy product greater than 1000, we left the numbers standing next to each other, unmultiplied, and waited for an opportunity to cancel.  Once the cancelling is finished, we only have to multiple 2 single-digit numbers: much much more manageable than multiplying 56*27 to get 1512, and then trying to divide that by 24!!

Again, if you simply can remember to cancel before you multiply, you will be way ahead of the pack in reducing seemingly intractable calculations to grade-school easiness.

GMAT (No Calculator!) Practice Problems

1) This year, Sheila will make $58,200.  This will be a 20% increase over her income last year.  Last year, she paid 4.8% of that year’s annual salary in taxes (federal, state, and local).  What is the dollar amount she paid in taxes?

  1. $582
  2. $2328
  3. $11,640
  4. $16,296
  5. $27,936

2) Two small area rugs have the same area.  The first is a square, 36 inches on each side.  The second is a rectangle 24 inches wide.  What must be the length of the rectangular rug?

  1. 36
  2. 40
  3. 48
  4. 52.5
  5. 54

3) A gigantic municipal retaining wall is 38.7 feet tall by 1178 feet long.  The side that faces the city needed to be repainted.  A single gallon of specialty paint will cover 296 sq ft of the surface. How many gallons will need to be purchased to paint this wall?

  1. 73
  2. 112
  3. 155
  4. 215
  5. 497

Answers

1) B.

2) E.

3) C.

1) Here, the exact numerical calculations would be ugly, and the answer choices are nicely spread out.  This problem is simply screaming for solution by estimation.  Estimate Sheila’s salary this year as $600000.

120% of last year = $60000

Divide by 6

20% of last year = $10000

Now, multiply by 5 to get 100%.

100% of last year = $50000

Now, estimate the percentage of her taxes as 5%

5% of $50000 = 0.05 x $50000 = $2500

The only answer that is anywhere near that is answer choice B.

2) The square rug has an area of 36 x 36, and the rectangular rug has an area of 24L, where L is the unknown length we need to find.  The areas are equal, so we have

[pmath]36*36 = 24L

Keeping our principle in mind, we will not find the product of 36 x 36, unless threatened at gunpoint.  Divide by 24 to isolate L

L = {36*36}/24

 

Cancel a factor of 12 from the 24 and one of the 36′s

L = {36*3}/2

 

Now, cancel the factor of 2 in the denominator with the other 36, and everything simplifies to

L = 18*3 = 54

Answer choice E.

 

3) This is a BIG wall, and again, the problem is crying out for estimation.  Let’s estimate the dimensions of this wall as 40 ft by 1200 ft.  The area would be 40 x 1200 sq ft; again, no reason to multiply those, because we know that this product has to be divided by something.  Estimate that a single gallon of paint will cover 300 sq ft.  The number of gallons needed would be

number of gallons = {40*1200}/300

Divide the 300 into 1200 — it goes into it four times.

number of gallons = 40*4 = 160

By far, the closest answer choice is answer choice C.

No calculator, no problem!  :)

 

About the Author

Mike McGarry is a Content Developer for Magoosh with over 20 years of teaching experience and a BS in Physics and an MA in Religion, both from Harvard. He enjoys hitting foosballs into orbit, and despite having no obvious cranial deficiency, he insists on rooting for the NY Mets. Follow him on Google+!

18 Responses to Can You Use a Calculator on the GMAT?

  1. Felice February 25, 2014 at 5:48 am #

    I was assuming a calculator could be used, however I know that since it can’t be used the writers of the questions cant go too into craxy detail.

    Is there a section I should focus more on? I am afraid I will spend more time concentrating on a problem and having time go by which can screw me in the end. I gave myself almost 4 months to study.

  2. Jessica February 9, 2014 at 9:14 pm #

    Thanks for the tips! I’ve got my nose in a book and am looking for all the advice I can get before sitting for the GMAT! I feel like I haven’t seen some of this material since high school! Thanks for all the links as well!

    • Mike
      Mike February 10, 2014 at 9:57 am #

      Dear Jessica,
      You are quite welcome. Have courage, my friend! You can learn all of this and be good at it. Best of luck to you!
      Mike :-)

  3. Joy February 8, 2014 at 6:14 am #

    Am still scared about no calculator thing….really haven’t been a math fan from time but just happens I have to take GMAT..please can I have your email?so,u can help me out more please….

    • Mike
      Mike February 8, 2014 at 3:35 pm #

      Dear Joy,
      My friend, relax. Math is like a muscle. If you have not been a math fan, and have avoided math for years, then when you start practicing, it will be like starting to jog or rock-climb — it will be a difficult and painful experience at first. You have to trust that, as with any physical activity, with repeated practice, you will get yourself in shape and have an easier time.
      I definitely recommend that you read through every math article I have written on this blog, because I discuss several tricks you can use to simplify calculations. Here is a good one with which to start:
      http://magoosh.com/gmat/2012/number-sense-for-the-gmat/
      Also, practice mental math every day. Every single day, force yourself to do at least one addition, one subtraction, one multiplication, and one division in your head. Have a roommate or friend standing by with a calculator to check you. Again, this will be very difficult at first. The key is to practice consistently, faithfully, and it will become easier over time.
      If you join Magoosh, we have a whole series of math video lessons that can help you. If you want to ask me about individual math questions, you can post question in the Magoosh section of GC:
      http://gmatclub.com/forum/magoosh-324/
      Finally, fear never helps you study. You need to have the confidence that you can do this well. Here’s an article about stress reduction:
      http://magoosh.com/gmat/2012/overcome-gmat-exam-anxiety-breathe/
      I hope all this helps.
      Mike :-)

  4. Alex F. January 30, 2014 at 6:57 pm #

    Excellent info, thanks. However, for question #2 I solved it in an even easier way: 36 inches = 3 feet, so the square and rectangle both have an area of 9 sqft. 24 inches = 2 feet, so the length of the rectangle is 9/2 = 4.5 feet, or 54 inches.

    • Mike
      Mike January 31, 2014 at 10:04 am #

      Alex,
      Yes, for this particular problem, you could simplify with a change from inches to feet — it’s always worthwhile to have your antennae up for such simplifying switches. Also, this same problem could have been given with 36 units, etc., in which case you would have to work with the larger numbers efficiently. It’s important to have those skills as well. (Of course, even if they give generic “units”, you can pretend that they are feet, inches, meters, etc. if that assumption leads to simplifying calculations as it did here.) It’s important to have as many options as possible when approaching calculations without a calculator.
      Mike :-)

  5. Kristina January 7, 2014 at 8:26 pm #

    This is great! Thank you! I am actually looking forward to the GMAT now.

    • Mike
      Mike January 8, 2014 at 10:02 am #

      Dear Kristina,
      You are quite welcome! I’m glad you found it helpful! Best of luck to you!
      Mike :-)

  6. Aaron August 28, 2013 at 3:08 pm #

    Thanks SO much. You just pushed my prep score from 20% to 80% in five minutes.

    • Mike
      Mike August 28, 2013 at 3:23 pm #

      Aaron,
      You are quite welcome. I’m glad you found this helpful. Best of luck to you.
      Mike :-)

  7. Alex Sackman June 26, 2013 at 3:22 pm #

    This is very helpful, thank you for this posting.

    • Mike
      Mike June 26, 2013 at 4:32 pm #

      Alex,
      You are more than welcome. I wish you much success on the GMAT.
      Mike :-)

  8. Stephanie May 30, 2013 at 7:45 am #

    This helps a lot! Thank you!

    • Mike
      Mike May 30, 2013 at 10:15 am #

      Stephanie,
      You are more than welcome. Best of luck to you!
      Mike :-)

  9. Marie March 30, 2012 at 7:41 pm #

    I rely too much on calculators that I easily get stressed with having to do even little mental computations. I think my mind’s a little bit rusty for now but I’ll start doing some mental “jogging” this time . Thanks for the tips!

    • Mike
      Mike April 3, 2012 at 11:43 am #

      Marie: you are quite welcome. Thank you for the kind words. Good luck with your preparation, and let us know how we can support you.
      Mike :-)


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