What did avogadro actually do that resulted in avogadro's number?

The Number Of Atoms (or molecules) In A Mole of a Substance. Equal to 6.02214179 × 1023 per mole.

Yes

atoms in 12 g of c-12

Avogadro number refers to the number of molecules in 12 gram of C-12. Number of molecules clearly implies that Avogadro no. is natural number.

Avogadro's number is the number of "elementary entities" (usually atoms or molecules, ions, electrons, protons etc.) in one mole. Its value is 6.0221415 × 1023. There are 6.0221415 × 1023 atoms per...