1. Significant Numbers All numbers in a measurement that are reasonable and reliable

2. RULES FOR DETERMINING SIGNIFICANT DIGITS 1.All non zero digits are significant digits 2.Captive zeros (zeros trapped between non zero numbers) are always significant 3.Leading zeros are never significant 4.Trailing zeros are only significant if there is a decimal place present.

3. Rules continued 5. Counted numbers have an infinite number of significant digits 6. A decimal point may be used to make zeros significant digits 7. In exponential numbers,only the numeric portion of the number may be used when considering the number of sig figs. The exponent places the decimal point and is not significant.

4. Significant figures in numeric calculations Remember a calculated result can be no more precise than the least precise piece of information that went into the calculation

5. MULTIPLICATION/DIVISION When multiplying and dividing your final answer MUST contain only as many significant figures as the least precisely known quantity in the calculation.

6. ADDITION /SUBTRACTION When adding and subtracting your answer MUST be expressed with the same number of decimal places as the quantity carrying the smallest number of decimal places