$\"\"$

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The expression is $\"\"$ .

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$\"\"$ (Substitute $\"\"$ )

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To subtract an integer , add its opposite.

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Opposite of $\"\"$ is 6.

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$\"\"$ (Add 6 to 20)

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$\"\"$ (Add: $\"\"$ ) $\"\"$

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To subtract an integer , add its opposite.

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Opposite of 5 is $\"\"$ .

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$\"\"$ (Add $\"\"$ to 26)

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$\"\"$ (Add: $\"\"$ ) $\"\"$

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The value of the expression when $\"\"$ is 21.