Easy Math trick you won't learn at school

#fastmathtricks
#mentalmath

[ninjakille]

Surprisingly, I learned this in school. My history of math class covered how some ancient civilization (Egyptians I think) added, subtracted, multiplied, and divided this way. I think this method can help people better understand how numbers interact, but it's different than the mental math tricks that your channel is known for.

[affzor]

18*32 = (20-2)*(30+2) = 600 + 40 - 60 - 4 = 576 is the way to go. Works with all numbers and fast af.

[rsmeditation]

I like the way this chap uses methods that are quick, but at the same time are written down so you see how it works. As opposed to pure mental arithmatic. Not as fast as Arthur Benjamin but still fun to use. Nice 'fall back' method.

[DJKav]

Giving children or non math thinkers, many more ways to solve the same problem is always a good thing. With people, there's no, 'one way - fits all' strategy. Nothing to do with speed, just more methods that you might click with and understand.

[lifelyrics]

I am now 20+ and i still practice all your math techniques. Sales go so much easier and calculating houses sq feets are made easier without calculator

[iYakuza]

20 * 32 - 2 * 32
OR
18 * 30 + 2 * 18
Just multiply the bigger/lower number with the closest multiple of ten of the lower/bigger number and subtract/add up the multiplication between the difference between the rounded number and the lower/bigger number with the bigger/lower number.

[klaymonkey]

I usually just times them out. But it's a cool trick. A good learning exercise for people who get lost in large numbers.

[crosssans]

There is I think the way faster trick to these calculations. For Example:
12 x 12 = ?
Calculating this is very simple.
12 x 12 = ?
^ ^
We will multiply this together and we will put 4 at the end.
12 x 12 = 4
2 * 2 = 4
Then we will multiply 1 x 2 & 2 x 1
12 x 12 = 4
^^ ^^
2 x 1 = 2
1 x 2 = 2
Then we will add up
2 + 2 = 4
We will add to the result
12 x 12 = 44
Then we will multiply these first numbers which in this case are 1
1 x 1 = 1
We will add to the result
12 x 12 = 144

[mehmetalidemir]

Really nice trick for children and young people who have issues with multiplying.

[kshrubb]

Awesome trick! Super easy if you're used to doing 2^x or binary stuff.

[estebanzd]

Well, this is something I'm going to keep in my mind while doing multiplication with a power of two. Even if you guys say it's slower/equally slow. I love the number two.

[rsmeditation]

Wow, what a fantastic video! Wish they'd shown us this stuff in school!

[Aviatr]

Very interesting how it works and work it does.

[Whatsthemata]

love your vids, not hating, but wouldnt that take longer than just multiplying in your head?

[tom_the_pianoman]

Nice Video, but I think it would be good to explain why the Trick works like it does and why it can be used everytime regardless of the Numbers (some people doesn't get this)

[malterator]

Hi I need to get lantite ready and wondered if you have any guidance i.e. what sections of yours should i review and how to get ready. Every time i do a class of yours i understand but am really concerned as i have not been in a classroom for over 40 years. thanks

[Sarahmint]

Do another set of numbers so we know exactly what you did.

[diaryofhope]

He helped me pass 4th grade know i am in 5th grade but forgot all the tricks so i came back

[MarkBowenPiano]

What happens with something like 27 x 45?

[Fraugrin]

In a test w/o calculator this is amazing