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.