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### Course: Arithmetic>Unit 17

Lesson 2: Multiplying and dividing decimals by 10, 100, and 1,000

# Multiplying and dividing decimals by 10

This video explores the concept of multiplying and dividing decimals by 10, 100, and 1000. It demonstrates how each digit in a number shifts places when multiplied or divided by powers of 10. The video emphasizes understanding place values and how they change in these operations.

## Want to join the conversation?

• When dividing 3 by .6 is this the method that I can use?

(3 x 10 ) divided by (.6 x 10)
30/6 simplified 15/2
And that’s how you do it or did I miss a step or didn’t do something correctly I need to under stand better the concept of this method
• That is a very good way of doing it, move the decimal in the denominator until you get a whole number then move numerator the same amount (multiply by 10 is same as moving decimal).
• Is Mr. Sal Khan multiplying or dividing 67.5 by one tenth?
• He is multiplying and dividing by one 10, so x 10. For example, 42 x 10 you just have to add a extra 0, the way you know how many 0's is by looking behind the number putting the 0's behind the other number.
Hope this helps
• how do i do something like this 2.34 multiplied by 4000 and the same with dividing
• Well you could do it like this: take the 2.34 and move the digits over three spaces (using the same method you would with a 10) to the left to make 2340. Then multiply that by 4 (from the 4000) to get 9360.

And as for division, just do the same thing but slightly reversed. Move 2.34 three spaces to right to get 0.00234. Then divide that by 4 (smh) to get 0.000585. And if you're not sure, just check your calculator.

Hope this clears thing up a little for ya :D Peace
• I still don't get it. Can anyone tell me an easier way?
• An easier way is to think about it by look at the number like for example, 23 x 10. When you look at it you just think of it of adding an extra 0. So it would be 230, with a hundred it would be adding two extra 0's and so on.
Hope this help
• Can I use the calculater to calculate hard eqations?
• If you do the arithmetic by hand, then it gives you good practice so that you'll be faster and more accurate, as you won't have a calculator beside you every time. Plus, it's good to know what a calculator is doing. However, if you really truly know how to do the math and have mastered it, there's no sense in doing long, tedious problems by hand all the time. Then you can use a calculator.
Typically, you'll see more calculators the higher up you go in math, as it's expected that everyone knows basic arithmetic, so that isn't tested.
• i watched it a few times an i am getting them all right
• I thought we were multiplying, not dividing.
• Actually, we're doing both. That's why the title of the video is Multiplying and dividing decimals by 10
• hey!! if you still need help, examples are that he's basically saying that on a place value chart, if i were to have 39.8, it would look like this;
tens|ones|.tenths
3 | 9 |. 8
but if we were to multiply that by 10, it would move a space to the left, therefore it would look like this;
hundreds|tens|ones
3 | 9 | 8
and the decimal point would be gone

for division, it's the opposite, you move a space to the right,
originally, 36.9 would like this;
tens|ones|.tenths
3 | 9 | . 8
though, when we divide it by ten, it would change to
ones|.tenths|hundreths
3 | . 6 | 9
hope that helped!! ^^
my apologies, however, that the digits aren't lined up, i can't find a way to fix that