The answers (with the sig fig in each number underlined):

 

Number

Sig Fig

Number

Sig Fig

Number

Sig Fig

4.90

3

0.00120

3

0.001060

4

56.0020

6

000200.000

6

780.

3

0.0018

2

.0018

2

1.8x10-3

2

Note that the last row shows three different ways to express the same number to the same sig fig.