Question Video: Finding the Result of Column Addition of Three-Digit Numbers by Regrouping Ones | Nagwa Question Video: Finding the Result of Column Addition of Three-Digit Numbers by Regrouping Ones | Nagwa

Question Video: Finding the Result of Column Addition of Three-Digit Numbers by Regrouping Ones Mathematics • Second Year of Primary School

What is the result of the following operation?

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Video Transcript

What is the result of the following operation?

And if we look at the way that this calculation has been written, we can see that it says 668 plus 212. So the operation that’s mentioned in our question is an addition. We need to find the total of 668 and 212. And because these two numbers have been written so that the ones digit, the tens digit, and the hundreds digit are all in separate columns, we call this column addition. And we need to find the answer by adding each column separately.

Let’s begin with the ones. Eight ones and two ones are quite nice numbers to add because they make a pair that we should know already. Eight and two go together to make 10. And so the total of our ones is 10 ones. But we can’t write two digits in the ones place. How can we show 10 ones? Well, one thing we know about place value is that 10 ones are worth exactly the same as one ten. So we can take our 10 ones and exchange them for one ten.

Now, sometimes when we record our one extra ten that we need to add on, we might write it underneath the equal sign here, very small, just to remind us not to forget it when we add the tens. But can you see the way that this calculation has been written? There’s a little box for it at the top. So that’s right, our one extra ten in that box. And we know that 10 is made up of one ten and zero ones. So we’ve still made a total of 10. We’ve just regrouped it in a different way.

Now, let’s add the tens digits. Six tens plus one more ten makes seven tens. But don’t forget the extra ten we made when we added those ones. Our total is going to not be seven tens, but eight tens. Finally, let’s add the hundreds. 600 plus two more hundreds equals eight hundreds. We’ve added these two three-digit numbers simply by adding the ones, then the tens, and then the hundreds. And the only part we really needed to be careful about was when we had to regroup those 10 ones and also when we had to remember to add that extra 10. The result of the operation 668 plus 212 is 880.

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