1 of them.
One and it is 7
There is only one significant figure which is the 7. When zeros are placed before a number, they are not considered significant figures.
One. The zeros to the left are only position placeholders; they are not significant digits.
Two significant figures.
Leading zeros are not significant digits, therefore 007 has one.
Two of them and they are 1 and 8
4 significant figures.
There are 4 significant figures in 0.0032. Seems to be only 2 significant figures in this number.
There are 3 significant figures in 94.2.
3 significant figures.
4487 has four significant figures.
101330 has 6 significant figures.