What is the nuclear mass of helium 3 (³He) of which the atomic mass is 3.016030 u?

There are 2 electrons as the proton number for helium is 2. 

We need to take away the mass of two electrons (P)

Nuclear mass = 3.016030 u – (2 ´ 0.000549 u) = 3.014932 u (P)