Are these chemistry answers correct?

Question

The question is determine the number of significant figures and identify the applicable rules.

1. 127.50 km = 5

2. 1200 km = 2

3. 90027.00 cm2 = 7

4. 0.0053g = 5

5. 670 mg = 2

I have no idea what an applicable rule is so can someone please a

Explain that?

Answer 1

All is correct except number 4. the sig fig is 2 because the Zeroes are place holders. NOW HELP ME SOOMEONE!!!!!

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