Explanation:
The greatest common factor (GCF) of 4 and 10 is 2.
To find the GCF of two numbers, you need to identify the factors that the numbers have in common and then find the greatest of those factors.
The factors of 4 are 1, 2, and 4.
The factors of 10 are 1, 2, 5, and 10.
The only factor that 4 and 10 have in common is 2. Therefore, 2 is the greatest common factor of 4 and 10.