Question

Order from greatest to least. 65 x 104, 432 x 103, 2.996 x 104

a. 432 x 103, 65 x 104, 2.996 x 104

b. 65 x 104, 432 x 103, 2.996 x 104

c. 2.996 x 104, 432 x 103, 65 x 104

Answer 1

You can work this out quickly by approximations
65 x 104 ~ 65*100=6500
432 x 103 ~ 43*100=4300
2.996 x 104 ~ 3*100 = 300
Now you can order them any way you wish.
Notice that here the numbers are wide apart, so approximation works well.