<p> Significant Figures</p><p>All nonzero digits are significant. To determine if a zero is significant follow these 4 rules:</p><p>1) RULE 1. Zeros between numbers (“sandwiched”) are significant. Thus, 94.072 g has five significant figures.</p><p>2) RULE 2. Zeros to the left of a number are not significant; they act only to locate the decimal point. Thus, 0.0834 cm has three significant figures, and 0.02907 mL has four.</p><p>3) RULE 3. Zeros to the right of a number after the decimal point are significant. Thus 138.200 cm has six significant figures. </p><p>4) RULE 4. Zeros to the right of a number before the decimal point may or may not be significant. For example, we cannot tell whether 300 has one, two, or three significant figures. However, if it is in scientific notation, any zero to the right is significant. For example 3.00 x 102 has three significant figures and 3.0 x 102 has two.</p><p>Doing Calculations</p><p>Often when doing calculations, we end up with an number whose significant figures we must decide. How do you decide how many digits to keep? There are two simple rules to follow:</p><p>RULE 1. In carrying out a multiplication or division, the answer cannot have more significant figures than either of the original numbers.</p><p>RULE 2. In carrying out an addition or subtraction, the answer cannot have more digits after the decimal point than either of the original numbers.</p>