Warm Up #2 1. Put these metric prefixes in order, starting with the smallest: A. kilogram B. milligram C. decigram D. microgram

Significant Figures Unit 1

Significant Figures (the dreaded Sig.Fig.) 123 = 3 sig figs 101= 3 sig figs 100.= 3 sig figs where 100= 1 sig figs Used to ensure precision in our calculations Cookbook methodology: Non-zero digits are ALWAYS significant Zeros between whole numbers are significant A trailing zero is significant only if there is a decimal point

Significant Figures (the dreaded Sig.Fig.) Zeros before whole numbers are not significant, EVEN after a decimal For a decimal number the very last zeros count as significant In scientific notation, all digits are significant except for powers of 10* Any zero with a line over it is a significant figure 0.00243= 3 sig figs 7.01044400kg = 9 sig. figs 108.0 x 104 = 4 sig figs 175,000 = 5 sig figs

complete the left side of “How Many Significant Digits for Each Number complete the left side of “How Many Significant Digits for Each Number?” Wroksheet With a partner

complete the right side of “How Many Significant Digits for Each Number?” Wroksheet Alone

Rounding off Significant Figures Determine the number you wish to round. Round the number: Is the number after higher than a 5? If so, round up. Is the number after lower than a 5? If so, leave the number as is. Is the number after a 5? Follow these steps: Is the number you are rounding an even number? KEEP IT THE SAME Is the number you are rounding an odd number? ROUND UP TO AN EVEN NUMBER

Rounding with Addition and subtraction Count the number of significant figures in the decimal portion of each number in the problem. (The digits to the left of the decimal place are not used to determine the number of decimal places in the final answer.) Add or subtract in the normal fashion. Round the answer to the LEAST number of places in the decimal portion of any number in the problem.

Rounding with Multiplication and Division Count the number of significant figures of each number in the problem. Multiply or Divide in normal fashion. The LEAST number of significant figures in any number of the problem determines the number of significant figures in the answer.

Scientific Notation Used to simplify complex numbers Cookbook methodology for positive exponents: Move the decimal point till only one whole digit is to the left of the decimal point. Write the new number followed by x 10 The number of times you moved the decimal point in step one will become your exponent 102,000,000,000 1.02 1.02 x 10 1.02 x 1011

Scientific Notation Using negative exponents: Move the decimal point till only one whole digit is to the left of the decimal point. Write the new number followed by x 10 The number of times you moved the decimal point in step one will become your exponent. This time add a negative. 0.00000000789 7.89 7.89 x 10 7.89 x 10-9