Perhaps, you are talking about the following undergoing chemical reaction:
Thus, balancing it by inspection, one obtains:
In such a way, a 3 (three) must be placed in front of the calcium chloride in order to balance calcium and consequently the rest of the chemical reaction.
3 to balance the calciums on both sides of the equation, but only if that balances the Cl on both sides of the equation to because you now have 6 Cl and 3Ca