1. Fun Fact Your stomach has to produce a new layer of mucus every two weeks otherwise it will digest itself

2. Scientific Notation A given number is written as the product of two numbers » 10000 = 1 x 10 4 – Numbers greater than ten have positive exponents 123,000,000,000 = 1.23 x 10 11 – Numbers less than ten have negative exponents » 0.000 000 007 51 = 7.51×10−9

3. Practice Convert the following to scientific notation – 3427 –.0473

4. Significant figures Significant Figures- – Include all the digits that are known plus a last digit that is estimated

5. Rules for Significant Figures 1. Every nonzero digit is significant – 24.7 714 Each have three sig. figs. 2. Zeros between non-zeros are significant – Example: 7003 (four sig. figs.) 3. Zeros in front of nonzero number is not significant – Example:.0071 (two sig. figs.)

6. Rules for Significant Figures 4. Zeros at the end of a number to the right of the decimal are always significant – Example: 43.00 (four sig. figs.) 5. Zeros at the rightmost end of a measurement with no numbers to the right of the decimal are not significant – Example: 7,000 (one sig. fig.)