WEBVTT
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We know that eight plus seven equals 15.
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Here are the four number sentences for eight, seven and 15.
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Eight plus seven equals 15.
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15 subtract seven equals eight.
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Seven plus eight equals 15.
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And 15 subtract eight equals seven.
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Here are some number sentences for five, six, and 11.
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Six plus five equals 11.
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11 minus five equals six.
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Five plus six equals 11.
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Which number sentence for five, six, and 11 is missing?
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If we colour-code the numbers in the same way as the first group of sentences, it helps us to see the pattern.
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The commutative property tells us it doesnâ€™t matter which order we add the numbers.
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The answer is still the same.
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11, six plus five makes 11.
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And five plus six makes 11.
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We know that the missing number sentence is a minus because there are two addition facts and two subtraction facts for each group of numbers.
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We already have 11 take away five.
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So if we switch these numbers, we will get the missing sentence, which is 11 take away six equals five.
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The missing sentence is 11 take away six equals five.