Question

is four, fine salt, and sugar pure substances or mixtures? i know that you have to combine some elements to get them, but i want to double check.

Answer 1

double check what?
what was your answer?

Answer 2

I'm thinking they are pure substances, but wanted to check

Answer 3

I assume you made a typo on four and you meant flour. Most flours are mixtures. Pure salt is a pure substance of sodium chloride but the salt you buy at the store is "iodized salt" and contains a small amount of NaI. Technically it is a mixture, also. You can buy "un-iodized" salt and that is pure.
White sugar(refined sugar) is pure C12H22 O11. Brown sugar (unrefined) is a mixture. It contains molasses.