There are 3 sigfigs in 100. because there is a decimal after the second zero, indicating that the units digit matters. If there is no decimal place, then the zeros are considered place holders and thus would be 1 sig fig only. But since there is a decimal, the former is true.
1
there are 3 sig figs. 4, 0, and 5 are the sig figs
5 sig figs
There are four sig figs in 1.032
There are four sig figs in 2.905.
There are 4 sig figs in 20.13
There are four sig figs in 60.55.
There are eight sig figs in 57.115102.
There are three sig figs in 4890.
All five of them are sig figs
61 has 2 sig figs.
There are five sig figs
There are three sig figs in 1.05.