This talk will focus on applications of hashing. We use Leftover Hash Lemma to count linearly independent polynomials defined on a given set. From this we will derive a recent result of Abbe, Shpilka and Wigderson on linear independence of random tensors. Unfortunately, methods based on hashing only work over finite fields. A totally different approach to random tensors was found by Pierre Baldi and myself, which I will explain in detail.