This is a balanced chemical equation for the reaction between calcium hydroxide $Ca(OH)2$ and phosphoric acid $H3PO4$ to form calcium phosphate $Ca3(PO4)2$ and water $H2O$.

Ca$OH$2 + 2H3PO4 -> Ca3$PO4$2 + 6H2O

This balanced equation shows that one molecule of calcium hydroxide reacts with two molecules of phosphoric acid to produce one molecule of calcium phosphate and six molecules of water.