Here's how to determine the number of atoms in C4H12O6:

* Count the subscripts:

* Carbon (C) has a subscript of 4, meaning there are 4 carbon atoms.

* Hydrogen (H) has a subscript of 12, meaning there are 12 hydrogen atoms.

* Oxygen (O) has a subscript of 6, meaning there are 6 oxygen atoms.

* Add the atoms together: 4 + 12 + 6 = 22 atoms

Therefore, there are 22 atoms in a molecule of C4H12O6.