請教TTGWD21-10

oneseven

Q10:

If d = 1/(2^3*5^7) is expressed as a terminating decimal, how many nonzero digits will d have?

A.     One

B.      Two

C.     Three

D.     Seven

E.      Ten

Answer: B

但是實際算出來是 1/625000

應該是答案C

請指教...謝謝

fly_holly

B

denominator is 2^3*5^7=2^3*5^3*5^4=10^3*5^4

d=1/10^3 *1/5^4=1/10^3 *1/25 *1/25=1/10^3*0.04*0.04...