Question

Which represents the smallest number A.3.8 x 10^7 B.3.8 C.3.8*10^-18 D.3.8*10^15

Answer 1

Arranging these numbers in a vertical column makes it easier to rank them by size:

A.3.8 x 10^7

B.3.8

C.3.8*10^-18

D.3.8*10^15

That factor 10^15 in D is by far the largest power of 10 in this list. The correct answer is D.