Multiplying decimals: place value and reordering | Decimals | Pre-Algebra | Khan Academy

We want you to develop an intuition about how to work with decimals. Understanding how you can rewrite decimals by considering the place value will help you multiply!

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Pre-Algebra on Khan Academy: No way, this isn't your run of the mill arithmetic. This is Pre-algebra. You're about to play with the professionals. Think of pre-algebra as a runway. You're the airplane and algebra is your sunny vacation destination. Without the runway you're not going anywhere. Seriously, the foundation for all higher mathematics is laid with many of the concepts that we will introduce to you here: negative numbers, absolute value, factors, multiples, decimals, and fractions to name a few. So buckle up and move your seat into the upright position. We're about to take off!

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[peterthepizzaguy]

The bit at the end helped a lot. Thanks.

[aliceclementine]

This video taught me more about this than my school teachers.

[shubhadayanand]

Wow!! Very good explanation. More than ‘HOW?’ you teach ‘WHY?’

[lordsofvegas]

This really helped, thanks! I still need to watch it a few more times though lol. <3

[lulu]

They're simplifying 2.91 and 3.2 into 291 / 100 and 32 / 10 and turning it into an expression.. 291 x 32 / 100 / 10 ( / = Divide ) and simplifying that expression and multiplying 100 x 10 which is 1, 000.
They turned that expression now into 291 x 32 / 1, 000, multiplying first getting 9, 312 and dividing it by 1, 000 getting 9.312 (going to the left three times)

[josemorales]

There is also a much easier way of multiplying decimals. You could line up the decimals and add zeros if needed.

[juliecallaghan]

Thanks helped me heaps I don't even need my maths teacher any more

[prremlatarai]

Helped me very much! Just ignore the haters!

[cbougie-]

Nobody: Me: how does this guy have that much subs but not much likes 🤔

[mrgabehallsclass]

That’s a lot of problems, math and words when u can simply say “how many you bump the decimal out is how many you have to bump it back in at the end. “

[datFloyd]

Wouldn't 2.91 x 3.2 be 291 x 320 ?
Shouldnt it be 2.91 x 0.32 for it to be 291 x 32 or am I thinking wrong?

[pranavy]

this is more simple than the way I do it

[DaFan]

Thanks Sal, btw you sound sick in this video, if you are, then feel better! 

[nikkichristinek]

Am I the only one who found this very confusing??!

[jamil]

Can you please help me understand this or maybe do a video demonstrating it how to solve it on paper. 73x154 = 11242 down the value of 112420 /Divided by 0.73 =

Thanks.

[jehanahmed]

You said 9 x 3 =28 it's not 9x3=27

[crxcked]

he did 2 x 9 instead of 9 x 3 that was a mistake

[thecozybungalow]

Mad confusing! There is no easier way? I hate math!

[iluvyoukevinn]

kool aid




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