It can't be one. Mixed numbers are greater than one.
0800 001 001
There is no moshling 001.
Without a decimal point, they are both the same. If you asked "Which is less .01 or .001", then .001 is the smaller number.
It is 12 because 001 is the same as 1
The 0005 is larger without a decimal points. If you meant .001 and .0005, the .001 is larger.
.001
001
+001 and the us number
001 then the us number
It is one thousandths.
.001
It is: 0.004