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:

I find myself constantly using long division and multiplication for simple things like 13 x 11.

What are some good arithmetic calcs to memorize? I created a 20x20 multiplication table but this seems like a bit much right?

Perfect squares up to 100? \(\sqrt{3}\)? \(\sqrt{5}\)?

I am not really talking about formulas to memorize since you should definitely memorize things like nCr, nPr, sum of all #'s in an evenly spaced set, etc.

This file should give you an idea where you are lacking. I think you should definitely know the squares from 0-10 and preferrably from 10 to 20 as well.

Re: What arithmetic should I memorize? [#permalink]

Show Tags

31 Oct 2009, 08:56

46

This post received KUDOS

38

This post was BOOKMARKED

I'm new here, and try to go through all the topics - this site is a treasure!

Maybe not the right place to share my experience with "multiplication for simple things like 13 x 11", but anyway...if you need to multiply any two-digits number by 11, just sum those digits and put the result in between. For example, 13x11 -> 1+3=4 -> 143 is the result. Or, 36x11 -> 3+6=9 -> the result is 36x11=396.

Re: What arithmetic should I memorize? [#permalink]

Show Tags

31 Oct 2009, 19:21

21

This post received KUDOS

20

This post was BOOKMARKED

Shelen wrote:

I'm new here, and try to go through all the topics - this site is a treasure!

Maybe not the right place to share my experience with "multiplication for simple things like 13 x 11", but anyway...if you need to multiply any two-digits number by 11, just sum those digits and put the result in between. For example, 13x11 -> 1+3=4 -> 143 is the result. Or, 36x11 -> 3+6=9 -> the result is 36x11=396.

It really saves time.

And if it equals more than 10, add a 1 to the first digit

Re: What arithmetic should I memorize? [#permalink]

Show Tags

09 Jan 2010, 19:05

1

This post received KUDOS

Shelen wrote:

I'm new here, and try to go through all the topics - this site is a treasure!

Maybe not the right place to share my experience with "multiplication for simple things like 13 x 11", but anyway...if you need to multiply any two-digits number by 11, just sum those digits and put the result in between. For example, 13x11 -> 1+3=4 -> 143 is the result. Or, 36x11 -> 3+6=9 -> the result is 36x11=396.

Thanks for the tips. I recently downloaded some math apps to learn shortcuts. I plan to use them minimially though given the geometry and other formulas I need to memorize. It really saves time.

Re: What arithmetic should I memorize? [#permalink]

Show Tags

11 Feb 2010, 21:41

11

This post received KUDOS

19

This post was BOOKMARKED

Guys! I just found another way of checking whether a number is divisible by 8 or not ( the rule is same but another approach or route ). It's for a number with more than two digits.

Let's take 1936 1) First of all check whether last two digits of the number are divisible by 4 or not. For 1936, we do this way 36/4=9

2) If it is divisible by 4 then add the quotient to the 3rd last digit of the number and if the sum of them is divisible by 2 then the whole number is divisible by 8.

--> 9 (quotient)+ 9 ( 3rd digit from right)= 18, and -->18/2=9 So the whole number is divisible by 8.

Once you understand it and do a little practice, you'll find it easy and fast. **You can try other numbers to see whether it is true or not Hope it helps!
_________________

"I choose to rise after every fall" Target=770 http://challengemba.blogspot.com Kudos??

Re: What arithmetic should I memorize? [#permalink]

Show Tags

14 Feb 2010, 05:12

3

This post received KUDOS

2

This post was BOOKMARKED

AtifS wrote:

Thanks for sharing the Doc bb...@Shelen & @jeckll...Thanks for the tip but I would like to add some more.

What if u need to multiply 3 digits or 4 didgits by 11...the procedure is same as u mentioned but it would be done like below

For 3 digits 133x11 --> 1 1+3 3+3 3=1463 And for 4 digits 1243x11 --> 1 1+2 2+4 4+3 3=13673

And for 5 digits 15453x11 --> 1 1+5 5+4 4+5 5+3 3=169983 and so on. you can plug other numbers in and check it out.

Hope it helps!

welldone dude, just a small addition which i tried and will help to avoid confusion:

start writing the answer from right hand side in case if the addition of two no. exceeds 10, and add it to consecutive no. on left hand side. try out!!
_________________

"Great people don't do different things, they do things differently"

Re: What arithmetic should I memorize? [#permalink]

Show Tags

14 Feb 2010, 05:21

3

This post received KUDOS

3

This post was BOOKMARKED

AtifS wrote:

Guys! I just found another way of checking whether a number is divisible by 8 or not ( the rule is same but another approach or route ). It's for a number with more than two digits.

Let's take 1936 1) First of all check whether last two digits of the number are divisible by 4 or not. For 1936, we do this way 36/4=9

2) If it is divisible by 4 then add the quotient to the 3rd last digit of the number and if the sum of them is divisible by 2 then the whole number is divisible by 8.

--> 9 (quotient)+ 9 ( 3rd digit from right)= 18, and -->18/2=9 So the whole number is divisible by 8.

Once you understand it and do a little practice, you'll find it easy and fast. **You can try other numbers to see whether it is true or not Hope it helps!

hi, i feel the process is bit complicated as it doesn't give the value of quotient, it just tells you whether no. is divisible by 8. here is another tric, if the no. formed by last three digits is divisible by 8 then the whole no. is divisible by 8.

953360 is divisible by 8 since 360 is divisible by 8, 529418: not divisible as 418 is not divisible by 8.

plug in different values and try.
_________________

"Great people don't do different things, they do things differently"

gmatclubot

Re: What arithmetic should I memorize?
[#permalink]
14 Feb 2010, 05:21

Its been long time coming. I have always been passionate about poetry. It’s my way of expressing my feelings and emotions. And i feel a person can convey...

Written by Scottish historian Niall Ferguson , the book is subtitled “A Financial History of the World”. There is also a long documentary of the same name that the...

Post-MBA I became very intrigued by how senior leaders navigated their career progression. It was also at this time that I realized I learned nothing about this during my...