Adding 3-digit numbers (no regrouping) | 2nd grade | Khan Academy

• [Voiceover] So I have two numbers here that I wanna add together. The first number is 327, and that means three hundreds. I have a three in the hundreds place. You see them right over here. You see the three hundreds, each of these big squares have a hundred little squares in 'em, so three of them is going to be three hundreds.

And then I have two tens. Two tens, the two is in the tens place, so this is the two tens right over here. And then I have seven ones. The seven is in the ones place. Seven is in the ones place, and you see the seven ones. Seven ones, right over there.

Now, this is three hundreds, two tens, and seven ones, or 327. Now, to that, I wanna add 251, or another way of thinking about it as I wanna add two hundreds, because the two is in the hundreds place, two hundreds. Two hundreds. One hundred, two hundred.

Fifty is the same thing as five tens; we see a five in the tens place. Five, let me do that same color. Five tens, right over here. One ten, two tens, three tens, four tens, five tens. And then finally, I have a one in the ones place, so that just means one one. You see that right over there. This is one. One one.

Now, pause the video, and see if you could add these two numbers together. All right, now let's do it together. So we have seven ones, and to that we're going to add one one, so how many ones is that going to be? Well, seven ones plus one one is going to be eight ones. You see here, seven, and then you have an eighth one. So eight ones, seven plus one is eight.

Now let's look at the tens. I had two tens, and I'm gonna add five more tens. You put 'em all together, you're going to have seven tens. Two tens plus five tens, you're going to have seven tens.

And then, finally, if you have three hundreds and you add two more hundreds, how many hundreds are you going to have? Well, you're going to have five hundreds. You see these five groups of a hundred right over here. So you're gonna put a five in the hundreds place.

So 327 plus 251 is 578. Five hundreds, seven tens, and eight ones.