When it comes to measurements in the physical sciences, determining significant figures is a crucial skill. From converting measurements, to really any type of equation used in science, using significant figures is the required way to give an estimated answer.
Determine if the number is a non-zero digit.
If the number is a zero, determine if it is between two non zero digits.
If the number is a zero, determine if it is in a number without a decimal point.
If the number is a zero, determine if it is to the right of the last non-zero digit within a set of numbers.