Answer:
The greatest common factor between 30 and 70 is 10
Explanation:
first break down each number into its prime factorization in the case of 30 that would be 5,2,3. The prime factorization for 70 is 7,5,2 The prime factors that 70 and 30 have in common are 5 & 2. multiply 5 * 2 to get 10. 10 is the greatest common factor of 70 and 30