[求助]GWD-21-10

菲菲

Q10:

If d = 1/(2^3x5^7) is expressed as a terminating decimal, how many nonzero digits will d have?

 A.     One

 A.     One

B.     Two

C.     Three

D.     Seven

E.      Ten

Could anyone provide a systematic method to solve the problem?

菲菲

Understood, thanks!

qwrersaa

Look for pairs that'll give you 10s.  For example, in this question:

2^3 * 5^3 = 10^3

and you have 5^4 left, which gives you 10^-3 * 5^-4 = 10^-3 * 0.2^4 = 10^-3 *

0.0016

B