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# Multiplying decimals and whole numbers with visuals

Multiplying whole numbers and decimals can be fun. It starts with simple examples, such as multiplying 3/10 by 4, and then moves on to more complex examples, such as multiplying 52/100 by 3. In each case, we demonstrate how to use a number line or model to visualize the process and find the product. Created by Sal Khan.

## Want to join the conversation?

• the dude is awesome
• tbh he his he has helped me alot :D
• i don't get it or any math for that matter but i'm trying as hard as i pssibly can
• So, basically how I do this is I treat the decimal as a whole number by just ignoring the decimal point for now. I still leave it in for further reference like placing the decimal point. I multiply the two numbers, then I see how many decimal places there are before the decimal, and I skip that same amount of places in the product. This part is crucial, one place off and you get the wrong answer.
**Simplification Example**
5.4 x 63
5.4 --> 54
63 --> 63
54 x 63 = (50 x 4) x (60 x 3)
= (50 x 60) x (4 x 3)
= 3,000 x 12
= 36,000
5.4 has three decimal places in it, so skip three places from 0 in 36,000, your product.
36,_0,_0,_0.
I'm sorry if some of the math here was done wrong but I hope you get the point.
• i love number lines!!

they make math easier to understand, especially when first learning something.
• 👾👾👾Gamers
(1 vote)
• Upvote if you have 90000 energy points
• please someone say I agree this guy is awesome because he helps a lot! :)
• Upvote if u hav 90000 energy points
• 0.33 x 3 = 0.99
If you get this good just keep scrolling but if you don’t might wanna read this mini article.
So on that number line you can see everything marked of in tenths and you can see on there three tenths or 0.3 or 3/10 whatever you want to call it but anyways you can think of it like Sal says as the multiplication of a decimal and you can count 1 x 3/10, 2 x 3/10, 3 x 3/10, and 4 x 3/10 so what’s marked there is 4 x 3/10 so we want to know what that is going to be equal to we have to go from 3/10 to 6/10 to 9/10 to 12/10 or as a simplified fraction 1 2/10. Then he asks us all what’s 3 x 0.2 and he wants us to put it on the number line so what we would do is you would find out we’re that 2/10 is marked and you can go 1/10 and then 2/10 then we want to multiply it by three and that would be 0.6.
That’s enough for now I need a break from weighting for a while see ya!
• Very much appreciated! You seemed like you spent a lot of time on this!
• how would this apply to like say, 0.05 X 70?
• Hi,
Well, like shown in the video:
0.05 x 70:
5 x 70 = 350
Then, add up the number of place values after the decimal point, which is in this case 2.
3.50
You can ignore all the zeroes after a nonzero digit (after the decimal point, that is).
0.05 x 70 = 3.5