The GCF of 25 and 10 is 5.
10
10
Only if you're comparing a number to itself. The GCF and LCM of 10 and 10 is 10.
The factors of 10 are 1, 2, 5, and 10. There's no such thing as the GCF of a single number, only of two or more.
4.
15
It is: 5
It is: 6
It is 15
7
It is just 1
1