Answer:
has 4 significant figures
has 2 significant figures
has 3 significant figures
Explanation:
has 4 significant figures
We start counting from the first significant number which is 3.
We need to count the zero as well because it appears after a significant number.
has 2 significant figures
We start counting from the first significant number which is 1.
has 3 significant figures.
The first significant number here is 6.