what is the answer of
16=4*4=
81=9*9=
100=2*5*2*5=
12*12=
144=3*4*3*4=
What are you calling the "answer"? Do you want all the prime factors?
16 = 4*4 = 2*2*2*2
81 = 9*9 = 3*3*3*3
100 = 2*5*2*5 has already been prime factored as far as you can go.
Try 144 yourself