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## 3rd grade

### Course: 3rd grade > Unit 3

Lesson 4: Adding with regrouping within 1000# Using place value to add 3-digit numbers: part 1

Let's explore adding two 3-digit numbers using place value and carrying. We walk through the process step by step, starting with the ones place, then the tens place, and finally the hundreds place. We emphasize the importance of understanding what carrying means and how it relates to place value. Created by Sal Khan.

## Want to join the conversation?

- I have discalcula. Is there anyway to simplify this? I feel embarrassed being 33 and totally lost when trying to solve this problem. I cannot add 8+6 in my head because I cannot see the numbers on my fingers. When you start to add "ten's and hundred's" into the equation, I am totally lost...(156 votes)
- Timothy:

It is all a matter of memorization. You can get flash cards and quiz yourself. Or, like Hum said, put out blocks. Try a real life example. You could use pencils for example. Take 8, add 6. Count as you add them.(8 votes)

- How many different ways of addition can be used?(46 votes)
- Addition can be used almost anywhere whereas carrying can't. Addition can be used for fractions, only carrying can't.(33 votes)

- Is there anything that some people do that can help me get addition facts down in my head? I feel like I don't have anyone to talk to about this because my parents are always helping my brother with his home work.(8 votes)
- Write Notes that's the key to helping you organize information, don't write too much about the Concept to explain it just keep each Step short as possible but providing enough info telling you what to do then draw in some examples for you to look back at as you're learning, if you Color Coordinate write in to do that and why like... What you get confused by but again keep it short, just think about whether you NEED to make a Note of something or not if you can remember something without doing so, Carrying Numbers thou it's defo one to make note of.

I suggest using Google Docs if you have a Google Account which you'll use with YouTube, go to the Google search engine page, click the icon with the 9 Dots at the Top/Right of the page and click Google Drive or Google Docs, they're both connected to each other so doesn't matter which you go but in Google Drive you can create Folders and organize Documents you create.

I suggest creating a Folder for Maths then in that Folder right click in a blank area and click Google Docs and it will create a new Document for you. The rest is simple too you've got the Word Processor bit and the Toolbar above where you can select the Font, the Size, make Titles of each Concept Bold or change the Text Color. Or you could just write notes in a Lined Paper Pad but Google Docs you're not likely to lose any of your Notes and you can make copies.(0 votes)

- is there 123,456,256,453(4 votes)
- Yes, there is a 123,456,256,453. Numbers go on forever and ever. Numbers never stop.(2 votes)

- but who made math? plz tell me :((5 votes)
- Sal Khan made this math(1 vote)

- I need help with the adding 3 digit numbers(3 votes)
- Addition of 3-digit numbers

Three-digit numbers sum is as simple as the sum of two-digit numbers and requires you only to learn with the sum of single-digit numbers and how to deal with carries.

Steps to add 3-digit numbers:

Step 1: Place the given 3- digit number below the another given 3-digit number and arrange them into columns according to their places like ones, tens, and hundreds.

Step 2: Now start adding columns in a sequence starting from ones.

Step 3: When the sum of two digits in once’s column is greater than 9 like 8 + 5 = 13, then put 3 in the result and pass 1 as a carry to the tens’s column which will add with numbers present in that column. This carry concept is the same for all the columns.(1 vote)

- why can't we just add without regrouping?(4 votes)
- It's all about place value. We need to keep the tens in the tens place, the hundreds in the hundreds place, and so on. If we added together without regrouping, ex: 15+15, we would get the wrong answer 210. We already used the tens place so we bumped it over, making 10+10 wrongly equal 200. We have to keep everything in its right column to get the right number instead of crazy huge ones. If we regroup the 1 in 10 to the left and then ADD ON THE REST OF THE TENS, we would get the correct answer 30.

Good question. ^_^(2 votes)

- Can you please talk slower(4 votes)
- I was just wondering why would we not just add the numbers like they are instead of carrying?(2 votes)
- I think of carrying like this:

if I had lots of oranges in two groups I need to know how many tens, hundreds, etc, there are so I add and I regroup.(3 votes)

## Video transcript

Let's add 536 to 398. I'm going to do it two
different ways so that we really understand what this
carrying is all about. So first we'll do it in
the more traditional way. We start in the ones place. We say, well, what's 6 plus 8? Well, we know that 6
plus 8 is equal to 14. And so when we write it down
here in the sum, we could say, well, look, the four is in the
ones place, so it's equal to 4 plus one 10 So let's write
that one 10 in the tens place. And now we focus
on the tens place. We have 1 ten, plus
3 tens, plus 9 tens. So what's that going to get us? 1 plus 3 plus 9 is equal to 13. Now, we have to remind
ourselves, this is 13 tens. This is 13 tens. Or another way of thinking
about it, this is 3 tens. This is 3 tens and 100. You might say, wait, wait. How does that make sense? Remember, this is
in the tens place. When we're adding a 1 ten
plus the 3 tens plus 9 tens, we're actually adding 10 plus 30
plus 90, and we're getting 130. And so we're putting the 30. The 3 in the tens place
represents the 30. So this is the 3. The 3 represents the 30. And then we're placing this
1 in the hundreds place. 10 tens is equal to 100. And now we're adding
up the hundreds place. 1 plus 5 plus 3 is
equal to-- let's see, 1 plus 5 is equal to 6,
plus 3 is equal to 9. But we have to remind
ourselves, this is 900. This is in the hundreds place. So this is actually 100-- I want
to make all colors the same. So this is actually
100 plus 500 plus 300. Let me get the
color coding right. Plus 300 is equal to 900. And that's exactly
what we got here. 100 plus 500 plus 300 is
equal to 900, and we're done. This is equal to 934.