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Current time:0:00Total duration:2:38

- [Instructor] In this video, we want to figure out what
is equal to eight plus seven. And I'm gonna give you
a little bit of help by drawing what is known as ten frames. And these are useful
because as you can see, each of these frames
have ten boxes in them. One, two, three, four, five, six, seven, eight, nine, 10. Or you could see that it has five and then another five, so a total of 10. So we can represent each of these numbers in their own ten frame, so we could view this as eight, so we can fill in eight of these squares. One, two, three, four,
five, six, seven, eight. And that's going to be eight plus seven. So let's fill in seven of those squares. One, two, three, four,
five, six, and seven. So using this all as a hint, what is equivalent to eight plus seven? Pause this video and
try to think about it. All right, now let's do this together. So the reason why ten frames are useful is you can think about
how many would you have, how many of these circles
would you have to move from this ten frame into
this ten frame on the left in order to fill it up, and order to have 10 right over here? And you can see that we
have two spaces to fill up. So what if we were to remove
two of these yellow circles into this left ten frame? What would then happen? So I'm going to erase
this one and this one, and remember that I didn't lose them. I just have to put them
in a different place now. I'm going to put those
two right over here. So one and two. So notice, I still have
the same number of circles. I still have those seven yellow circles. One, two, three, four, five, six, seven. But I just wrote it a little differently so that two of them fill
up the left ten frame. Now this helps us think
about what this sum is going to be, why is that? Because now we filled out all the squares in this left ten frame. So we know that this left
side right over here, this is going to be 10, and now what's left in this right side? Well, this right side,
you can see we filled out half of the ten frame. Or one, two, three, four, five squares. So eight plus seven is
same thing as 10 plus five, which you might recognize
is going to be equal to 15. And you can obviously verify
that by counting all these. We have 10 here, and
then 11, 12, 13, 14, 15.