$\"\"$

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The expressions are $\"\"$ .

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Average number

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$\"\"$

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$\"\"$ (Write $\"\"$ as $\"\"$ ) $\"\"$

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$\"\"$ (Apply distributive property: $\"\"$ )

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$\"\"$ (Subtract: $\"\"$ )

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$\"\"$ (Divide: $\"\"$ ) \ \ $\"\"$

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The scientific notation is $\"\"$ .