**Lemma** means a proven statement.euclid's division lemma is an algorithm used to calculate highest common factor of two or more than two positive integers.

**Ex :-**

Let ‘a’ and ‘b’ be any two positive integers. Then there exist unique integers ‘q’ and ‘r’ such that a = bq + r, 0 ≤ r ≤ b. If b | a, then r=0. Otherwise, ‘r’ satisfies the stronger inequality 0 ≤ r ≤ b.