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If there are 342 boys and 200 girls in a school, how many students are there?
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In this question, we’re given two parts of a whole amount.
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If there are 342 boys and 200 girls, to find the number of students there are, we know we need to add these two amounts together.
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In other words, what is 342 plus 200?
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Now there’s something interesting about the number that we’re adding on to 342 here.
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Can you see what it is?
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200 is a multiple of 100.
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It’s what we get when we count on in hundreds twice: 100, 200.
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And so to add 200 to 342, all we have to do is to think about the hundreds digits.
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And you know, before we even start, we can make a prediction here.
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We can say that the number of tens and ones are going to stay the same.
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342 has four 10s and two ones.
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And that’s why we know that our answer is going to have four 10s and two ones, too.
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We just need to think about combining our two 100s together.
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That’s 300 and another 200.
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Now we know three plus two equals five.
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So 300 plus another 200 is going to make 500.
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We found the answer quickly here, simply by adding on the hundreds that we needed to.
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If there are 342 boys and 200 girls in a school, the number of students that there are altogether is 542.