Like this? 234+34.1= 268.1 then round. If it is less than 5 then you round down if it is more then you round up. Because it is less the final number would be 268.1=268
The balanced equation for
Ca(OH)2 + H3PO4→ Ca3(PO4)2 + H2O is
3 Ca(OH)2 +2 H3PO4→ Ca3(Po4)2 + 6 H2O
3 moles of Ca(OH)2 reacted with 2 moles of H3PO4 to form 1 mole of Ca3(PO4)2 and 6 moles of H2O