WEBVTT
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Find the missing equation.
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Five take away one equals four.
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Five take away two equals three.
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What?
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Five take away four equals one.
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In this problem, we’re shown four pictures of ten frames, and they each show a subtraction.
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If we look at each ten frame, we can see that the top row of each one is completely full.
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In other words, we’re starting with five counters every time.
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That’s why when we look at the number sentences or equations that follow these pictures, we can see the number five is first.
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It’s the number we’re starting with.
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But can you see we don’t have a subtraction for our third picture.
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It’s missing.
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And the question asks us to find this missing equation.
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Well, we know which number to start with.
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Just like all the other pictures, we have five green counters to begin with.
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If we look at our first picture, we can see that we’re taking away a small amount of counters, one.
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Then in the second picture, we’re taking away one more than this.
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We take away two.
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By taking away one more each time, we know that we can find all the different possibilities.
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So if we take away two in this one, in the next calculation, we need to take away three.
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Let’s check the diagram to see if this makes sense.
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Yes, we can see that we’re taking away three out of our five counters.
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All we have to do now is to think about what the answer is going to be.
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What number goes with three to make five?
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We could imagine a cube train containing five cubes.
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And if we break it apart so that there are three in one group, we know that there’ll be two in the other group.
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Five counters take away three counters leaves us with two counters.
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And we can see in our last equation we take one more again.
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Five take away four this time equals one.
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We know that three and two go together to make five.
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And so our missing equation is five take away three equals two.