In this paper, we show a multiple-term refinement of Young?s type inequality
and its reverse via the Kantorovich constants, which extends and unifies two
recent and important results due to L. Nasiri et al. (Result. Math (74),
2019), and C. Yang et al. (Journal. Math. Inequalities, (14), 2020). An
application of these scalars results we give a multiple-term refinement of
Young?s type inequalities for operators, Hilbert-Schmidt norms, traces and
the unitarily invariant norms.