For an ordinary atom which contains protons, neutrons and electrons, the sum of the atomic number Z and the neutron number N gives the atom's atomic mass number A.
fɚɹən ˈɔːɹdɪnˌɛɹi ˈæɾəm wˌɪtʃ kəntˈeɪnz pɹˈoʊtɑːnz, nˈuːtɹɑːnz ænd ᵻlˈɛktɹɑːnz, ðə sˈʌm ʌvðɪ ɐtˈɑːmɪk nˈʌmbɚ zˈiː ænd ðə nˈuːtɹɑːn nˈʌmbɚɹ ˈɛn ɡˈɪvz ðɪ ˈæɾəmz ɐtˈɑːmɪk mˈæs nˈʌmbɚɹ ˈeɪ.