Step-by-step explanation:
It is known that an atom consists of protons, neutrons and electrons. Both protons and neutrons are located inside the nucleus of an atom whereas electrons revolve around the nucleus.
Atomic number is the total number of protons present in an atom. On the other hand, atomic mass is the sum of total number of protons and neutrons present in an atom.
That is, Atomic mass = no. of protons + no. of neutrons
no. of neutrons = atomic mass - no. of protons
Therefore, we can conclude that to find the number of neutrons in an atom, subtract its number of protons from atomic mass.