Hedgehog/Spike/For all statement/Exercise

We understand the statement "Hedgehogs have spikes“ as "Every hedgehog has at least one spike“. Which of the following statements are equivalent with the negation of this statement.

1. There does not exist a hedgehog which does not have a spike.
2. All hedgehogs do not have spikes.
3. There exists a hedgehog, which does not have a spike.
4. There exists a spike which does not belong to a hedgehog.
5. There exists a hedgehog without spikes.
6. There exist many hedgehogs without spikes.
7. There exists at least one hedgehog which has at least one spike.
8. There exists at least one hedgehog which has at most one spike.
9. Not every hedgehog has at least one spike.
10. Porcupines also have spikes.

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