# How many sodium atoms are represented in the formula 7Na_3PO_4?

What is 7xx3?
In one formula unit of $N {a}_{3} P {O}_{4}$, clearly there are 3 sodium atoms, 1 phosphorus atom, and 4 oxygen atoms. Do you agree?
So if we have seven formula units of $N {a}_{3} P {O}_{4}$, there are $7 \times 3$ sodium atoms, $7 \times 1$ phosphorus atoms, and $7 \times 4$ oxygen atoms.