2
0.00075kg is 750mg
231.57 has five significant figures/numbers. All the numbers in 231.57 are significant.
Assuming you mean percent of 100. It is .00075%
The figure 18.03 has a total of four significant numbers
Because 10.00400 is 10.004, this has five significant digits (numbers).
Three. All nonzero numbers are significant, and any zeros in between significant numbers are significant.
There are 5 significant figures.
1 significant figure.
5 significant figures.
Three significant figures.
Four significant figures.
Four significant figures.