All squares are parallelograms.
Negation: There exists at least one square which is not a parallelogram.
No squares are parallelograms.
Negation: There exists at least one square which is a parallelogram.
Some squares are parallelograms.
Negation: No square is a parallelogram.
Some squares are not parallelograms.
Negation: All squares are parallelograms.
Edwin
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