Lesson: Multiplying by Doubling and Halving

Comment on Multiplying by Doubling and Halving

I'm really enjoying these videos. Thanks!
gmat-admin's picture

Glad to hear you're enjoying them!

Great techniques. Thank you very much.
gmat-admin's picture

Thanks for that!

After this video, I had an "AHA!" moment lol, Thanks GMATPrep!
gmat-admin's picture

Good to hear!

Thank you

very cool, thanks

Very good and simple technique..
I liked it very much and it is very easy..
Thank you very much for explaning this technique..

nice .. i am gaining confidence step by step...

are the se all videos enough for decent scores as i dont want to waste my time on random resources ?
gmat-admin's picture

Yes, our course covers every concept and strategy necessary to beat the GMAT.

This is a great strategy!
Thanks!
Rashad046's picture

Although it has been more than 20 year ago, since I last sit math exams I do enjoy learning it againg with these videos
gmat-admin's picture

Glad to hear it!

Just to confirm this only works on products correct?
gmat-admin's picture

That's correct.

Euro's picture

good video

Alternatively, prime factorization for the numbers under the root =)
gmat-admin's picture

Yes, we could! That concept is covered later in the course, so I didn't discuss in this video.

These videos are such helpful! Wonderful job team. Kudos

Very easy and interesting techniques to learn

Why did I never knew this before? You're a genius! Thank you so much!

Wish they taught math in school this way :-) . thanks a ton! - Shiva

Another brilliant video!!

do you have slides for the video courses ?
gmat-admin's picture

We have 2 sets of flashcards (for GMAT math and GMAT critical reasoning) that are taken from slides of the course.
They can be found here: https://www.gmatprepnow.com/content/free-content

Cheers,
Brent

Not to sound stupid, but would this work under any circumstances for division?
gmat-admin's picture

Great question! I hadn't thought of that.

Since a ÷ b is the same as a/b, we can apply some nice fraction rules to division.
For example 17.5 ÷ 2.5 = (17.5)/(2.5)
Notice that we can take (17.5)/(2.5) and multiply top and bottom by 2 to create an EQUIVALENT fraction 35/5, which is much easier to evaluate.
So, 17.5 ÷ 2.5 = (17.5)/(2.5) = 35/5 = 7

So, if it helps us, we can take ANY division and multiply both parts by the same value to create an easier division.

Here's a quick one: 21/5 ÷ 7/5
If we multiply both parts by 5, we get: 21 ÷ 7, which is much easier to deal with.

Cheers,
Brent

Very helpful. Thank you so much :)

This is very useful. I have heard of this technique, and now, through this video, I understand how it works. Will practice to master it. Thanks!

the video is not working
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It works for me. Also, Vimeo, my video host, has not experienced any issues.

Can you please clear the cache of your Web browser, then restart your computer and see if that resolves the issue. Also, can you try another Web browser and see what happens?
Here are the instructions for clearing your cache: https://kb.iu.edu/d/ahic

Note: you need not clear your cookies or your browsing history.

A little more information about the issue will help resolve the problem as soon as possible.

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