Far from the center > each is not accurate (far from the truth) consistently wrong. Random errors = reduce precision poor accuracy and poor precision (person) Accuracy can be true of an individual measurement or the average of several. Precision requires several measurements before anything can be said about it. Report digits which are known with certainty. Resolution of measuring device influences the number of sig figs. Convention for indicating the number of sig digits. Trailing zeros without a decimal point -- 2,500. Exact numbers do not limit the number of sig figs. Exact conversions: 1 m = 100 cm. Multiply/divide: the number with the fewest sig digs determines the number of sig digs in the answer. Add/subtract: the last decimal places of the numbers determines the place of the last sig digit in the answer. Draw a line, my precision cannot be better than this digit and everything else should we dropped after rounding up to location.