Please explain

1. Counting atoms \begin{tabular}{|l|l|} \hline \multicolumn{1}{|c|}{ Compound } & \multicolumn{1}{c|}{ Total No. of Atoms } \\ \hline Mg3(PO3)2 & 3Mg+2P+60=11 \\ \hline Ca(PO4)2 & \\ \hline BeAl2(SiO3)6. gemstoneryl. The mineral which is the source of the \\ \hline(NH4)2SO3 & \\ \hline \end{tabular}