The answer according to my booklet is 1.6734×10-24 (g), but I don't understand how we got this answer.
proton: 1.6725×10-24
neutron: 1.6748×10-24
electron: 0.0009×10-24
To get the mass, I added protons with neutrons, but I got 3.3473×10-24.
What am I doing wrong?