2
It has 1 significant figure.
0.004 has 1 significant figure.
There is one significant figure in 0.3.
There is one significant figure in .00000004.
2 of them.
1 significant figure. It can also be written as 4x10^6 (one sig fig)
Two significant figure
One significant figure.
10 significant figures.
One significant figure
1 significant figure.
One significant figure.