Explain "By changing unit zero are added. This will not change number of significant digits.''

Explanation

Let mass of a pearl is 85 milligram which is measured upto accuracy of 1 milligram.
If this mass is measured in terms of gram it will be represented as 0.085. In this number there will be 2 significant digit.
Same mass is measured in terms of kilogram - 0,00 0085 kg. Here, also underlined zero are not significant digit. Therefore, no. of significant digit will be 2.
This shows that by changing unit no. of significant digit will not change.