1. Find the product (3  10 3 ) (7  10 5 ). Write the result in scientific notation. Exponents and Multiplication COURSE 3 LESSON 7-2 (3  10 3 ) (7  10 5 ) = (3 7)  (10 3 10 5 ) Use the Associative and Commutative properties. = 21  (10 3 10 5 ) Multiply 3 and 7. = 21  10 8 Add the exponents for the powers of 10. = 2.1  10 1  10 8 Write 21 in scientific notation. = 2.1  10 9 Add the exponents. 7-2

2. A light-year is 5.9  10 12 miles. A mile is 1.609  10 3 meters. How many meters are in a light-year? Write your answer in scientific notation. Exponents and Multiplication COURSE 3 LESSON 7-2 There are about 9.5  10 15 meters in a light-year. (5.9  10 12 ) (1.609  10 3 ) Use dimensional analysis: mi = m. m mi = (5.9 1.609)  (10 12 10 3 ) Use the Associative and Commutative properties. Multiply 5.9 and 1.609. Round to the nearest tenth. 9.5  (10 12  10 3 ) = 9.5  10 15 Add the exponents of the powers of 10. 7-2

3. Exponents and Multiplication COURSE 3 LESSON 7-2 1.Write (–8) 4 (–8) 5 using a single exponent. 2.Write the product of (8.2  10 6 ) and (5  10 2 ) in scientific notation. 3.The speed of light is 3.00  10 5 km/s. Find the distance light travels in 8  10 2 seconds. (–8) 9 4.1  10 9 2.4 X 10 8 km 7-2