Concept :
1. all non - zero digits are significant .
2. zeros present to left /right of a number are non - significant however zero present after decimal points are significant .
3. zeros present between two non - zero digits are significant .
(i) 0.0025
according to rule 2 , there are 2 significant figure in 0.0025.
(ii) 208
according to rule 1 and 3 , there are 3 significant figures in 208.
(iii)5005
according to rule 1 and 3, there are 4 significant figures in 5005.
(iv) 126000
according to rule 2,there are 3 significant figures in 126000.
(v) 500.0
according to rule 2 , there are 4 significant figures in 500.0
(vi) 2.0034
according to rule 2, there are 5 significant figures in 2.0034