How many significant digits are 0.1020?

Answer 1

0.1020 is a number to 4 significant figures.

The rule is that "Zeros must be kept to show the position of the decimal point or to indicate that zero is a significant figure."

Then the leading zero before the decimal point is retained as this shows the position of the decimal point.

The zero between 1 and 2 is a key part of the number.

The final zero (after 2) is a significant figure otherwise the number would be written 0.102.

Consequently, the 4 significant figures are "1020" but are presented as 0.1020 to ensure the true value of the number is accurately given.