Total number of atoms = 5
Further explanation
The formula of a compound shows the composition of the constituent elements
CaCO₃ is composed of 3 types of atoms, namely Ca, C and O
The amounts of each of these atoms in the compound CaCO₃:
Then total number of atoms :
![\tt 1+1+3=5](https://img.qammunity.org/2021/formulas/chemistry/high-school/rvbvql024fdk4ign59tq7wdaxd8np4xp3c.png)