When using a 100 mL graduated cylinder marked every 1 mL, there should be one decimal places in each reading. The first decimal place is an estimated because the graduated cylinder is marked for every 1 mL. The final definitive number is in the ones place, so the tenth place should be estimated, as the last digit of measurement is usually estimated. For example, on a 100ml graduated cylinder marked every 1 mL, a sample reading would be 75.6mL, three significant figures, because 75 would be shown in the graduated cylinder and I would estimate the tenth digit to be 6. I decided that .0304g has three significant figures because the first zero is is considered a place holding zero, so it is excluded, while the zero between three and four is included
