Write symbolic representation for the following word equation and balance them:
(a) Calcium carbonate → calcium oxide + carbon dioxide

Symbolic representation:
<!--td {border: 1px solid #ccc;}br {mso-data-placement:same-cell;}--> ${CaCO}_3$ → $CaO$ + <!--td {border: 1px solid #ccc;}br {mso-data-placement:same-cell;}--> ${CO}_2$
The equation is balanced, the number of atoms of each element on reactant and product side is equal.