How much spaghetti noodles would I need to feed 3 people? (1 adult, a preteen, and a little kid?)?

A 1 lb box makes 8 average portions, assuming you will have something else too. Since a box of pasta is cheap extra is not much of a problem, but a half box (8 oz) should be fine, no more than 3/4 of a lb max, good luck.

I think half a box (8 ounces) would be plenty.

A half of a pound should be plenty. That's usually half of a box.

1 box.

3/4 of a packet, 1 if you want leftovers. For something different, add tuna to the sauce, it's really yummy. Use 1 bottle of passata and 1 can. Fry some chopped onion and garlic, add the sauce and the can and cook it on a low simmer, add salt and fresh/dried herbs like parsley. Keep an eye on it, add a little water if it's too thick. Good luck.

A 16 oz package would feed 8 people. You may be able to find smaller packages, so basically you would need an 8 oz and have some left over.

2 oz. per person.
Since 2 of the 3 of You are young, You might need more!!
Kids love pasta, and leftovers make perfect snacks.

I would make at least 6 oz.
If I were You, I would make 10 oz.

Check out the link for measuring pasta by shape:

So 3 people altogeather or 4 including yourself? I would make if 3 or 4 people about 3/4 of a box.

An 8 oz box should do ya. Get a pound if you wouldn't mind a few leftovers.

I POUND SHOULD DO WITH A LITTLE LEFTOVER FOR LUNCH,ADD A LITTLE CHEESE AND MAKE GARLIC BREAD,WITH BUTTER,A FILLING MEAL BUT CHEEP TO MAKE

one pound should do -- you might have some left over