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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.
• Bruh thes something wong
(1 vote)
• and also couldn't you just do a fraction problem?
ok so say we have 52 hundredths right? we put a 1 under the 3 as 3 over 1 to make it a fraction.
then we do 52/100 *3/1
the answer is 156 over 100 or 156/100.
then divide. 156 divided by 100 is 1.56! 52*3 is 156!
so couldn't you just do a a fraction problem to make it easier?
I just do those to make it easy :D
• this dud helped me learn more than my teacher in math
• 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
• 100000x200000
• 20000000000
• my name is bob
• Okay when Multiplying decimals sometimes you do keep change flip that is when you have a problem like this

5/7 dived by 5/3
this is when you do keep change flip

5/7 x 3/5

15/35
I am no pro but I think this is how you do it and hope it helps