GWD21求助！！

orchidbrooks

21-Q10:

If d = 1/[(2^3)*(5^7)]                                  

  i s expressed as a terminating decimal, how many nonzero digits will d have?

 A.     One

B.     Two

C.     Three

D.     Seven

E.      Ten

答案:B 思路

orchidbrooks

谢谢!!!!!!!!!!!!

autumnjin

d＝1/[(2^3)*(5^3)*(5^4)] =  1/[(10^3)*(5^4)]  = 0.001/(5^4)=   0.001*(0.2^4)= 0.001*0.0001*16 

所以2个非零（1和6）