Thank you for using the timer - this advanced tool can estimate your performance and suggest more practice questions. We have subscribed you to Daily Prep Questions via email.

Customized for You

we will pick new questions that match your level based on your Timer History

Track Your Progress

every week, we’ll send you an estimated GMAT score based on your performance

Practice Pays

we will pick new questions that match your level based on your Timer History

Not interested in getting valuable practice questions and articles delivered to your email? No problem, unsubscribe here.

It appears that you are browsing the GMAT Club forum unregistered!

Signing up is free, quick, and confidential.
Join other 500,000 members and get the full benefits of GMAT Club

Registration gives you:

Tests

Take 11 tests and quizzes from GMAT Club and leading GMAT prep companies such as Manhattan GMAT,
Knewton, and others. All are free for GMAT Club members.

Applicant Stats

View detailed applicant stats such as GPA, GMAT score, work experience, location, application
status, and more

Books/Downloads

Download thousands of study notes,
question collections, GMAT Club’s
Grammar and Math books.
All are free!

Thank you for using the timer!
We noticed you are actually not timing your practice. Click the START button first next time you use the timer.
There are many benefits to timing your practice, including:

This is more about the relative scale of the quantities than anything. It's easier to think about it with numbers you can picture, so assume you have an equation like 1 000 000 000 (10^7) - 100 (10^2). This equation can still be approximated as 10^7, since the latter term is so insignificantly small compared to the former term.

Re: GMAT, Number Properties, Exponents [#permalink]

Show Tags

17 Jan 2012, 15:27

Expert's post

Baten80 wrote:

I found the answer options are: a. 10^210 b. 10^180 c. 10^150 d. 10^90 e. 10^6

I answered B. What is correct?

10^180 - 10^30 = Which of the following best approximates the value of the expression above?

Yes, answer 10^180 is correct. Note that we need approximate value of the given expression and as 10^(180) is much larger number than 10^(30) then 10^(30) is pretty much negligible in this case: 10^(180)-10^(30)=~10^(180).

Re: GMAT, Number Properties, Exponents [#permalink]

Show Tags

08 Jul 2013, 18:25

Bunuel wrote:

Baten80 wrote:

I found the answer options are: a. 10^210 b. 10^180 c. 10^150 d. 10^90 e. 10^6

I answered B. What is correct?

10^180 - 10^30 = Which of the following best approximates the value of the expression above?

Yes, answer 10^180 is correct. Note that we need approximate value of the given expression and as 10^(180) is much larger number than 10^(30) then 10^(30) is pretty much negligible in this case: 10^(180)-10^(30)=~10^(180).

Re: GMAT, Number Properties, Exponents [#permalink]

Show Tags

08 Jul 2013, 23:09

2

This post received KUDOS

Expert's post

cumulonimbus wrote:

Bunuel wrote:

Baten80 wrote:

I found the answer options are: a. 10^210 b. 10^180 c. 10^150 d. 10^90 e. 10^6

I answered B. What is correct?

10^180 - 10^30 = Which of the following best approximates the value of the expression above?

Yes, answer 10^180 is correct. Note that we need approximate value of the given expression and as 10^(180) is much larger number than 10^(30) then 10^(30) is pretty much negligible in this case: 10^(180)-10^(30)=~10^(180).

Re: GMAT, Number Properties, Exponents [#permalink]

Show Tags

09 Jul 2013, 00:27

cumulonimbus wrote:

Bunuel wrote:

Baten80 wrote:

I found the answer options are: a. 10^210 b. 10^180 c. 10^150 d. 10^90 e. 10^6

I answered B. What is correct?

10^180 - 10^30 = Which of the following best approximates the value of the expression above?

Yes, answer 10^180 is correct. Note that we need approximate value of the given expression and as 10^(180) is much larger number than 10^(30) then 10^(30) is pretty much negligible in this case: 10^(180)-10^(30)=~10^(180).

Hi Bunnel, Their are two sets of options on this page. How to decide b/w 10^180 and 10^179.

Hi cumulonimbus

I think 10^180 is closer. Because 1 is very small, 10^x - 1 is closer to 10^x than 10^(x-1).

Let try few examples, you can see the pattern. 10^2 - 1= 99 ==> closer to 10^2 = 100 than 10^1 = 10 10^3 - 1 = 999 ==> closer to 10^3 = 1000 than 10^2 = 100 10^4 - 1 = 9999 ===> closer to 10^4 = 10000 than 10^3 = 1000 ..... 10^180 - 1 ==> closer to 10^180 than 10^179

Hope it helps. _________________

Please +1 KUDO if my post helps. Thank you.

"Designing cars consumes you; it has a hold on your spirit which is incredibly powerful. It's not something you can do part time, you have do it with all your heart and soul or you're going to get it wrong."

Re: 10^180-10^30. Which of the following best approximates [#permalink]

Show Tags

27 Feb 2015, 10:56

Hello from the GMAT Club BumpBot!

Thanks to another GMAT Club member, I have just discovered this valuable topic, yet it had no discussion for over a year. I am now bumping it up - doing my job. I think you may find it valuable (esp those replies with Kudos).

Want to see all other topics I dig out? Follow me (click follow button on profile). You will receive a summary of all topics I bump in your profile area as well as via email. _________________

http://blog.ryandumlao.com/wp-content/uploads/2016/05/IMG_20130807_232118.jpg The GMAT is the biggest point of worry for most aspiring applicants, and with good reason. It’s another standardized test when most of us...

I recently returned from attending the London Business School Admits Weekend held last week. Let me just say upfront - for those who are planning to apply for the...