- Adding decimals: 9.087+15.31
- Adding decimals: 0.822+5.65
- Adding decimals: thousandths
- Subtracting decimals: 9.57-8.09
- Subtracting decimals: 39.1 - 0.794
- Subtracting decimals: thousandths
- Multiplying decimals example
- Multiplying challenging decimals
- Decimal multiplication place value
- Dividing decimals with hundredths
- Dividing by a multi-digit decimal
- Dividing decimals: hundredths
Multiplying decimals example
To multiply decimals, first multiply as if there is no decimal. Next, count the number of digits after the decimal in each factor. Finally, put the same number of digits behind the decimal in the product. For example, if we multiply 7.61✕9.2, we will have 3 digits behind the decimal in our product because there are 3 digits behind the decimals in the factors. Created by Sal Khan and Monterey Institute for Technology and Education.
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- Can you use Lattice multiplication while multiplying decimals?(259 votes)
- Yes. Draw your lattice, making sure to put the decimal in the correct place for each number. To figure out where the decimal belongs in your answer, put your fingers on each decimal in the numbers you multiplied together. Then, trace the decimals until your fingers meet at a corner in the lattice. Follow the diagonal from that spot to your answer. That is where your decimal belongs in the answer.(64 votes)
- how are some ways to multiply decimals(4 votes)
- Multiplying decimals is basically like multiplying non decimal numbers
follow the same steps as:
Always remember to line up your numbers correctly!
*If you need more detail in this answer, or you want another method, feel free to let me know!*
*I hope this helps!*(29 votes)
- I think this is my life now -_-(13 votes)
- hi! are all decimals tenths?(7 votes)
- no. just like regular place value, you can have tenths, hundredths, thousands, and others like you do in actual place value.(17 votes)
- hi everyone this video was amazing to me. you guys should see if there is one on world history.(9 votes)
- At2:13why does zero have no value? Why is it allowed to be cut out?(6 votes)
- The zero is a placeholder. You can take it out if you want. Her is an example:
placeholder --> 0.70 x 0.7
They are both the same(0.7 and .7
hoped that helps!
Oh, and Yes, if there is nothing after a zero in the whole number (ex: 387.900), then, yes, it is allowed!(4 votes)
- can a world history teacher assign khan academy or just a core math teacher and an elective math teacher because I'm in middle school the sixth grade(5 votes)
- Can you switch the numbers around and multiply and get the same answer?(2 votes)
- This is called the commutative property of addition and multiplication. Only with addition or multiplication can you switch the numbers around. So 2x3=3x2. You CAN'T do this with division or subtraction. 6/3 = 2 whereas 3/6 = 1/2 or 0.5.(4 votes)
- sorry if this isn't about the topic, but what's lattice multiplication?
- it's a Hindu-style multiplication https://en.wikipedia.org/wiki/Lattice_multiplication(2 votes)
- They did it not correct because they didn't put the dot together. and I want to be big.(3 votes)
We're asked to multiply 32.12, or 32 and 12 hundredths, times 0.5, or just 5 tenths. Now when you multiply decimals, you multiply them the exact same way you would multiply whole numbers, and then you count the number of spaces behind the decimal you have in your two numbers you're multiplying, and you're going to have that many spaces in your product. Let me show you what I'm talking about. So let's just multiply these two characters. So we have 32.12 times 0.5. And when you write them out, you can just push both of them all the way to the right. You could almost ignore the decimal. Right now, you should write the decimal where they belong, but you can almost pretend that this is 3,212 times 5, and then we'll worry about the decimals in a second. So let's get started. So if we were just multiplying 5 times 3,212, we would say, well, 5 times 2 is 10. Regroup the 1. 5 times 1 is 5, plus 1 is 6. 5 times 2 is 10. Regroup the 1. And then finally, you have 5 times 3 is 15, plus 1 is 16. And then we don't have any other places. If we were just doing this as 05, we wouldn't multiply 0 times this whole thing. We would just get 0 anyway. So just 5 times 3,212 gives us this number. But now we want to care about the decimals. We just have to count the total number of spaces or places we have behind the decimal point in the two numbers we're multiplying. So we have one, two, three spaces, or three numbers, to the right of the decimals in the two numbers that we're multiplying. So we need that many numbers to the right of the decimal in our answer. So we go one, two, three, put the decimal right over there. So 32.12 times 0.5 is 16.060. And this trailing zero right here we can ignore, because it's really not adding any information there. So we could just write this as 16.06. The last thing you want to do is just make sure that this makes sense. You have a number that's almost 32, and we're multiplying it by 0.5. Remember, 0.5 is the same thing as 5 over 10, which is the same thing as 1/2. So we're really multiplying 32.12 times 1/2. We're trying to figure out what one half of 32.12 is. And half of 32 is 16, and half of 0.12 0.06, so this makes complete sense.