Events & Promotions
|
|
GMAT Club Daily Prep
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
Track
Your Progress
Practice
Pays
Not interested in getting valuable practice questions and articles delivered to your email? No problem, unsubscribe here.
Apr 2610:00 AM EDT
-11:00 AM EDT
The Target Test Prep course represents a quantum leap forward in GMAT preparation, a radical reinterpretation of the way that students should study. Try before you buy with a 5-day, full-access trial of the course for FREE!
Apr 2711:00 AM EDT
-12:00 PM EDT
Prefer video-based learning? The Target Test Prep OnDemand course is a one-of-a-kind video masterclass featuring 400 hours of lecture-style teaching by Scott Woodbury-Stewart, founder of Target Test Prep and one of the most accomplished GMAT instructors
Apr 2808:00 AM PDT
-11:00 AM PDT
Whether you are just beginning your MBA journey or fine-tuning your path to a 700+ score, GMAT Day is designed to give you a competitive edge.
29 Jul 2012, 23:01
Kudos
Bookmarks
Example:
19*18=
1. Take the first number and add it with the units digit of the second number.
19+8=27
2. Multiply the result by 10
27*10=270
3. Multiply the units digit of the first number with that of the second number
9*8=72
4. Add the result of step 2 and 3 together
270+72 = 342
19*18=
1. Take the first number and add it with the units digit of the second number.
19+8=27
2. Multiply the result by 10
27*10=270
3. Multiply the units digit of the first number with that of the second number
9*8=72
4. Add the result of step 2 and 3 together
270+72 = 342
Archived Topic
Hi there,
This topic has been closed and archived due to inactivity or violation of community quality standards. No more replies are possible here.
Where to now? Join ongoing discussions on thousands of quality questions in our Quantitative Questions Forum
Still interested in this question? Check out the "Best Topics" block below for a better discussion on this exact question, as well as several more related questions.
Thank you for understanding, and happy exploring!
01 Aug 2012, 06:29
Kudos
Bookmarks
arnivorous
It would be much better to know the multiplication tables of numbers up to 19. Numbers up to 19 are used often and knowing their tables can speed up your calculations considerably
Then 18*19 is straight forward.
18*9 = 162. Write 2 and carry 16
18*1 = 18. Add 16 to get 34. You get 342.
Also, learning tables is not as hard as you might imagine.
e.g. 18*2 we know is 36. 18*3 is 18 more than 36
18*5 = 90 (12*5 = 60, 13*5 = 65, 14*5 = 70 and so on...). 18*4 is 18 less than 90. 18*6 is 18 more than 90
18*10 = 180. 18*9 is 18 less than 180.
All you really need to learn up is 18*7 and 18*8.
01 Aug 2012, 07:25
Kudos
Bookmarks
arnivorous
This is a translation of the algebraic multiplication of two numbers of the form 1a * 1b = (10+a)(10+b) = 100+10a+10b+ab. The latest expression we can also written it as (10+a+b)10+ab=(1a+b)10+ab.
I don't think the algorithm can be a real time saver. And its usage is quite limited (numbers below 20).
Many times, depending on the numbers, we can find specific shortcuts.
For example, 19 * 18 I would do it as (20 - 1) * 18 = 360 - 18 = 342, as it is always easy to multiply by 10 and 2.
Archived Topic
Hi there,
This topic has been closed and archived due to inactivity or violation of community quality standards. No more replies are possible here.
Where to now? Join ongoing discussions on thousands of quality questions in our Quantitative Questions Forum
Still interested in this question? Check out the "Best Topics" block above for a better discussion on this exact question, as well as several more related questions.
Thank you for understanding, and happy exploring!
