Main content

## Count unit squares to find area

## Video transcript

- [Voiceover] Each
small square on the grid has an area of one square unit. So, each of these small
squares is one square unit. This square is one square unit, and this square is one
square unit, and so on. And now we're asked to draw a rectangle with an area of 10 square units. Well, this word "area" here is talking about how much
space our shape covers. So, our shape in this case is a rectangle, so we're being asked to draw a rectangle that covers 10 square units, and we know that each of
these is one square unit, so we want a rectangle that
covers 10 of the square units. We could try just drawing a rectangle right across this top row until we get 10 square units, but the problem there is there's only one, two, three, four, five, six, seven square units going across the top. So we can't just do one
long row of 10 square units. We can't do one long column either, because one, two, three, four, five, six. Only six square units, so we can't draw a rectangle
going down like that either because we need 10 square units. So that means we're gonna
have to break up our 10 into equal groups. Since it can't all fit on one row, we're gonna have to break up
the unit squares into groups. So, we can break up a 10
into two groups of five, or five groups of two. Either one of those will work. So let's do that. Let's draw ourselves a rectangle, and we'll start up here. Here's a rectangle. And let's see, that's five. And we can space and make sure that covers the whole square unit. There we go. So here's our rectangle, and this rectangle covers one, two, three, four, five, there's the first row of five. And the second row of
five has unit squares six, seven, eight, nine, and ten. So, here's one perfect answer, a rectangle that has two rows of five square units, and we could've drawn this rectangle anywhere on the grid. It doesn't matter. We could've drawn it down here with two rows of five, or right here with two rows of five. Any rectangle covering two rows of five has an area of 10 unit squares. Similarly, any rectangle
covering five rows of two, let's look and see if
we can try to show that. Here we go. Here's a rectangle. And this one will cover one, two, so we have rows of two, and there's five rows. So, one, two, three, four, five, six, seven, eight, nine, 10. So again, this rectangle
covers 10 square units. So any rectangle you can draw on the grid that either covers two
rows of five square units or five rows of two square units is a rectangle with an
area of 10 square units.