About this video
A word problem asks how many cars a parking lot with 6 rows of 7 cars can fit. Sal shows how to ignore information that doesn't matter (opening time, wheels) and uses 6 x 7 = 42, checking it by skip counting and a diagram.
You'll be able to
- find the information a word problem really needs and ignore the rest.
- write a 'rows of' problem as a multiplication like 6 x 7.
- skip count by 7 to find 6 x 7 = 42.
Key words
- row
- A line of things side by side, like one line of parked cars.
- groups of
- Equal sets; 6 groups of 7 means six sets with 7 in each.
- skip count
- Counting by adding the same number each time, like 7, 14, 21.
Transcript
The local grocery store opens at nine. Its parking lot has six rows. Each row can fit seven cars. Each car has four wheels. How many cars can the parking lot fit? And I encourage you to pause the video and think about this yourself. Try to figure it out on your own.
So, let's re-read this. The local grocery store opens up at nine. Well, that doesn't really matter. If we're thinking about how many cars can the parking lot fit. So we don't really have to care about that. We also dont have to care about how many wheels each car has.
They're not asking us how many wheels can fit in the parking lot. So we can ignore that. What we really care about is how many rows we have. And how many cars can fit in each row. What we have is -- We have six rows and each row can fit seven cars. We're going to six groups of seven.
Or, another way of thinking about it. We're going to have six times seven cars can fit in the parking lot. What is this going to be equal to? This is literally six sevens added up. This is the same thing as one, two, three, four, five, six. That last seven looks strange.
Now we're going to add these up. Seven plus seven is fourteen. Twenty-one, twenty-eight, thirty-five, forty-two. Six times seven is equal to forty-two. So forty-two cars can fit in the parking lot. Don't believe me? I made a little diagram here. We have six rows.
This is the first row. Second.. Third.. Fourth.. Fifth.. Sixth. Each row can fit seven cars. You see it here. One; Let me make that a little brighter. One.. Two.. Three.. Four, five, six, seven. How many cars are there? You have seven. Fourteen.. Twenty-one.. Twenty-eight..
Thirty-five.. Forty-two total cars. Six rows of seven.
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