EN
We offer a complete answer to the following question on the growth of sumsets in commutative groups. Let h be a positive integer and $A, B₁, ..., B_h$ be finite sets in a commutative group. We bound $|A + B₁ + ... + B_h|$ from above in terms of |A|, |A + B₁|, ..., $|A + B_h|$ and h. Extremal examples, which demonstrate that the bound is asymptotically sharp in all parameters, are furthermore provided.