Is 0.1 km equals to 100.0 m (in context to significant figures)? The number of significant digits in 0.1km is 1 and we know that 1 km = 1000m.
This then implies that the 0.1 km is equal to 100.0 m, but the rule says the change in units doesn't affect the number of significant digits
 So how come the value in m has more significant digits?
I am really confused by it and the error I can find is that the value in m should be 100 m, then the number of significant digits would be same but then the question arises that can we remove decimal like this.

1 km is 1000m, so 100 000 cm, therefore you'll get 0.1km = 10 000cm. Both 0.1km and 10 000cm have the same number of significant digits. 
