Six
two sig figs
there are 3 sig figs. 4, 0, and 5 are the sig figs
2
5 sig figs
13.00 has 4 sig figs.
61 has 2 sig figs.
There are five sig figs
There are four sig figs in 2.905.
There are three sig figs in 1.05.
There are three sig figs in 4890.
All five of them are sig figs
There are two sig figs in 3700000.