10ab^5 = 2 * 5 * a * b * b * b * b * b
12ab^4 = 2 * 2 * 3 * a * b * b * b * b
16a^2b^3 = 2 * 2 * 2 * 2 * a * a * b * b * b
The GCF is made of the factors that appear in both 10ab^5, 12ab^4, and 16a^2b^3. In this case that's 2 * a * b * b * b = 2ab^3.
Answer: The GCF os 10ab^5, 12ab^4, and 16a^2b^3 is 2ab^3.