**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:

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

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

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.

Now, we notice that 8 divides evenly into 56

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

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?

- $582
- $2328
- $11,640
- $16,296
- $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?

- 36
- 40
- 48
- 52.5
- 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?

- 73
- 112
- 155
- 215
- 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 $60,000.

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

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

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

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

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

No calculator, no problem!

Thanks a lot for the questions and the explanations, Mike!

I just wanted to mention a couple of things. First, there’s a typo in your answer for question 1. You have written ‘Estimate Sheila’s salary this year as $600000′. It should be $60000. Nothing major, but it confused me for a couple of seconds.

Second, for this question, there’s an even faster way. I know you want to teach us how to estimate effectively and hence have not used this shortcut, but I just wanted to share this and get your opinion on the technique.

Since Sheila’s salary this year is a bit less than $60,000, if she paid taxes at the same rate as last year, she would have to pay a bit less than $3,000.

Now, at this point, we can reduce the amount by 20% (the increase in her salary) to get to $2,400, which will be closer to the actual amount she paid.

Or, since the answer choices are so spread apart for this question, we can just look at the answer choices, keeping in mind that last year she would have paid a lesser amount in taxes. And as you said, the only answer that is anywhere near that is answer choice B.

Dear Eshan,

Thank you for pointing out the typo. I just corrected it. And yes, that’s another good way of thinking about this problem. It’s a relatively straightforward problem to estimate in a few ways: the big idea, as you well understand, is not to get stuck on finding an exact numerical answer.

Best of luck!

Mike

Thank you very much Mike. I started my prep recently and am starting to have panic attacks. I thought I was really good in Math in High school but after all these years, I don’t remember anything and I am having a hard time in making mental calculations again. Your posts are helping me in attaining the right skill sets and building up my confidence again. Thank you very very much.

Dear Sin,

You are very welcome, my friend. I am very glad that you have found my advice helpful. If panic attacks are still a concern, I would also recommend this article and the subsequent ones linked to it:

http://magoosh.com/gmat/2012/overcome-gmat-exam-anxiety-breathe/

Best of luck to you!

Mike

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.

Felice,

I’m happy to respond. Is there a section on which you should focus more? I assume you mean one of the content areas in math. Well, in this post:

http://magoosh.com/gmat/2012/breakdown-of-gmat-quant-concepts-by-frequency/

we discuss the most frequently asked topics on the GMAT. The most frequent by far is Integer Properties, which is discussed here:

http://magoosh.com/gmat/2012/integer-properties-the-most-common-gmat-question-topic/

I hope that helps.

Mike

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!

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

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….

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

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.

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

pretendthat 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

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

Dear Kristina,

You are quite welcome! I’m glad you found it helpful! Best of luck to you!

Mike

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

Aaron,

You are quite welcome. I’m glad you found this helpful. Best of luck to you.

Mike

This is very helpful, thank you for this posting.

Alex,

You are more than welcome. I wish you much success on the GMAT.

Mike

This helps a lot! Thank you!

Stephanie,

You are more than welcome. Best of luck to you!

Mike

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!

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