Just leave them alone because they are already in 4 significant figures.
4 significant figures.
There are 3 significant figures in 94.2.
4 significant figures.
2.31 has 3 significant figures 4 has 1 significant figure 8.123 has 4 significant figures
There are 4 significant figures in 9.000.
4 significant figures.
5020 has 3 significant figures. It could also have 4 significant figures if, for example, 5019.6 was rounded to 4 significant figures.
19.6754 to 4 significant figures is 19.68
4487 has four significant figures.
There are four significant figures in 0.005120.
4 significant figures.