1. Aim: How can we perform mathematical calculations with significant digits? Do Now: State how many sig. figs. are in each of the following: 1.4.98 x 10 6 2.0.00209 3.872.010 4.9,501,000 33643364

2. Addition and Subtraction RULE: Round the answer to the least precise measurement. Ex: 10.26 131.5 + 12.862 Least Precise Measurement (fewest decimal places) 154.622 Round this answer to the least precise measurement (one decimal place) Answer: 154.6

3. Problems 1) 109.0006 5.23 87.11 + 9 -------------------------------------------------- 2)3.862 - 0.8943 3)123.456 7.89 + 0.12 ----------------------------------------------- 4)987.65 - 4 ---------------------------------------- 5)300,000,000 + 0.45 210 2.968 131.47 984 300,000,000

4. Multiplication and Division RULE: Round the answer to contain the same number of significant digits as the number with the least number of significant digits. Ex: 36.5 / 3.414 Least number of significant digits (3) = 10.69127124 Round the answer to 3 significant digits Answer: 10.7

5. Problems 1)27.3 / 4.2 2)49.2 x 87.61 3)(3.1 x 10 8 ) (2.98 x 10 4 ) 4)3.26 x 10 -4 / 4.2 x 10 -9 5)107.3 x 6 6.5 4.31 X10 3 or 4310 9.2 x 10 12 7.8 x 10 4 or 78,000 6 x 10 2 or 600 Note: It is a good idea to keep numbers in scientific notation when possible