Using “sí” and “no” with tener and venir?

Question

To say “I’m not” or “I don’t have,” do you use “no” just before tener?

Also, is it necessary to use “no” twice when answering a question negatively? I read you should use it once at the beginning of the sentence and once before tener.

Here are some practice sentences I wrote demonstrating my current knowledge. If I’m doing something wrong, please let me know. Thank you!

1. No, mi padre no tiene 50 años.
2. No, mis amigos no vienen a mi casa todos los días.
3. Sí, vengo a la universidad los martes.
4. No tengo hambre.
5. Sí, tengo dos computadoras.
6. Sí, tengo sed.
7. Sí, tengo que estudiar los domingos.
8. Sí, tengo una familia grande.

For example, for number 4, I'm not sure if "No tengo hambre" is correct or if I need to make it "No, no tengo hambre."

Answer 1

Your sentences are correct. If you want you could say "No" twice in #4 to add emphasis, but it´s not necessary.