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### Course: 6th grade > Unit 2

Lesson 1: Adding decimals# Adding decimals: 0.822+5.65

Adding decimals is a breeze when you follow these simple steps: First, line up the decimal points and write the numbers one below the other. Next, start adding from the smallest place value (thousandths) and carry over any extra value to the next place if needed. Finally, include the decimal point in your answer. Mastering decimal addition helps build strong math skills for everyday life.

. Created by Sal Khan.

## Want to join the conversation?

- Why do you put the smallest decimal on top and the longest decimal on the bottom?(17 votes)
- It doesn't matter which decimal value is longer or shorter to write, or which comes first or second…

In the video**Sal arranged the higher valued decimal on top**, (he placed the value with 5-whole over the 0-whole), and says**it is just his preference**, and it would add the same either way.0:10

because…

★**Addition**is**Commutative**, (*able to be rearranged and still add the same*).

2 + 5 = 7

5 + 2 = 7

★We can have**either decimal value on top or bottom**, but…

★ We**must LINE UP THE DECIMALS to keep each place value aligned**throughout the calculation.

0.822 + 5.65 = ?`0.822`

+ 5.65

————————

6.472 ←same answer

5.65

+ 0.822

————————

6.472 ←same answer

★**Use the decimals to guide the place value alignment: line up the decimals above and below,**, empty spaces are equal to zero.*then add each column of numbers*

(ㆁωㆁ) Hope this helps someone!(25 votes)

- hi

can you divide the ten by the two hundred(10 votes)- yes bc it will turn out to be 2000 thing for asking(7 votes)

- Hey, what if you had 9.78 - 3.2? What would I do with the 8?(11 votes)
- You would do 9.78-3.20 which would be 6.58(8 votes)

- in the equation, do you put 0.822 on the top or 5.65? its confusing...(9 votes)
- 5.65 on top and then you put a 0 after the 5 and then you put the 0.822 and add(4 votes)

- It doesn't matter which decimal value is longer or shorter to write, or which comes first or second…

In the video Sal arranged the higher valued decimal on top, (he placed the value with 5-whole over the 0-whole), and says it is just his preference, and it would add the same either way.0:10

because…

★ Addition is Commutative, (able to be rearranged and still add the same).

2 + 5 = 7

5 + 2 = 7

★We can have either decimal value on top or bottom, but…

★ We must LINE UP THE DECIMALS to keep each place value aligned throughout the calculation.

0.822 + 5.65 = ?

0.822

+ 5.65

————————

6.472 ←same answer

5.65

+ 0.822

————————

6.472 ←same answer

★Use the decimals to guide the place value alignment: line up the decimals above and below, then add each column of numbers, empty spaces are equal to zero.

(ㆁωㆁ) Hope this helps someone!(10 votes) - When exactly the "standard algorithm" happens in this solution?(6 votes)
- To use the
**standard algorithm**, follow these steps in order:**Line up the decimal points**`36.413`

12.5

+ 30.08

------------**Fill in the blank spots with zeros**`36.413`

12.500

+ 30.080

------------**Add, beginning with the smallest place first***thousandths*: 3+0+0=3*hundredths*: 1+0+8=9*tenths*: 4+5+0=9*ones*: 6+2+0=8*tens*: 3+1+3=7**Be sure to drop the decimal down into the answer**`36.413`

12.500

+ 30.080

------------

78.993

Hope this helps!(7 votes)

- Can you always do that stragegy(3 votes)
- how do you know if a decimal is a prime number(5 votes)
- Only natural numbers (integers above 0) can be considered composite or prime.(3 votes)

- they have should put this in the pre-school section. Its adding with an extra dot.(5 votes)
- I still don't understand this can someone explain this to me please.(4 votes)

## Video transcript

We're asked to
add 0.822 to 5.65. So let me rewrite this. And when I rewrite it, I
want to line up the decimals so that we add the right
place to the right place. And so we could write
either number first, although I like to write
the larger number first. So let's write 5.65. And remember, the
important thing is that we line up
the decimal points. So if we write 0.822-- so
we line up the decimal. Let me line up
the decimal first. So I'll write the decimal
right below the other decimal. And it is 0.822. And now we are ready to add. So let's see what's
going on here. So I like to start in
the smallest place. That way, the carrying
works out well. So you might say, wait,
I need to add this 2 thousandths to something. I don't see anything up here. Well, you could say there's just
a 0 thousandths right up here. Then it makes it very clear. Well, 0 thousandths
plus 2 thousandths is going to be 2 thousandths. 5 hundredths plus 2
hundredths is 7 hundredths. 6 tenths plus 8
tenths is 14 tenths. Well, 14 tenths is the same
thing as 4 tenths and 1 one. Another way of thinking about
it is you're carrying the 1. But really, what you're saying
is, look, this is 14 tenths. I could write it as 4 tenths
and a 1, or a ones place, a 1 in a ones place. Then you have 1 plus 5 is 6. And of course, you cannot
forget the decimal. The decimal goes right there. And this is 6.472.