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The cakes on display in a bakery are arranged in rows and columns.
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There are 15 cakes in five columns.
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How many rows of cakes are there?
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The first piece of information that we’re told in this problem is that the cakes on display in a bakery are arranged in rows and columns.
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The word we could use to describe the way that they’re set out is an array.
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The word array means exactly what the question says.
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It’s when items are arranged in rows and columns.
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Now, there are two things that we can say about arrays.
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The first is that they always make a rectangle shape, often an irregular rectangle, but sometimes a square.
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And the second thing we can say is that there a good way of representing multiplication and division facts.
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In this example, our array has two rows of four; that’s eight altogether.
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Two times four is eight.
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Let’s use our knowledge of arrays to help us solve this problem.
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The next fact we’re told is the number of cakes that are in the bakery altogether, and that’s 15.
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There are 15 cakes.
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We’re told that they’re arranged in five columns.
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These lines represent the five columns.
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But we don’t know the number of rows we’re asked.
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How many rows of cakes are there?
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In other words, we need to find out how many groups of five there are in 15.
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So to solve the word problem, we can see that we need to find the answer to a division number sentence, 15 divided by five equals what.
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Let’s build up an array using counters, and at the same time we’re going to skip count in five to find out how many five there are in 15.
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One row of five equals five.
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Two rows of five equals 10.
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Three rows of five equals 15.
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So we can see that we’ve skipped counted in fives three times to get to 15.
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Five, 10, 15.
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The number of fives in 15 is three.
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So we can say 15 divided by five equals three.
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If there are 15 cakes in a bakery and they’re arranged in five columns, then we know that the number of rows of cakes will be three.