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Learn to represent numbers by using exponents. Vocabulary. exponent base exponential form. Exponent. Base. An exponent tells how many times a number called the base is used as a factor. A number is in exponential form when it is written with a base and an exponent. 7 3.
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Vocabulary exponent base exponential form
Exponent Base An exponent tells how many times a number called the base is used as a factor. A number is in exponential form when it is written with a base and an exponent. 73 = 7 7 7= 343
Additional Example 1: Writing Numbers in Exponential Form Write each expression in exponential form. A. 5 5 5 5 B. 3 3 3 3 3 54 5 is a factor 4 times. 35 3 is a factor 5 times.
Check It Out: Example 1 Write each expression in exponential form. A. 7 7 7 B. 6 6 6 6 6 6 73 7 is a factor 3 times. 66 6 is a factor 6 times.
Additional Example 2: Finding the Value of Numbers in Exponential Form Find each value. A. 26 B. 45 26 = 2 2 2 2 2 2 = 64 45 = 4 4 4 4 4 = 1,024
Check It Out: Example 2 Find each value. A. 34 B. 25 34 = 3 3 3 3 = 81 25 = 2 2 2 2 2 = 32
1 Understand the Problem Additional Example 3: Problem Solving Application A phone tree is used to contact families at Paul’s school. The secretary calls 4 families. Then each family calls 4 other families, and so on. How many families will be notified during the fourth round of calls? The answer will be the number of families called in the 4th round. List the important information: • The secretary calls 4 families. • Each family calls 4 families.
2 Make a Plan You can draw a diagram to see how many calls are in each round. Secretary 1st round–4 calls 2nd round–16 calls
3 Solve 4 Look Back Notice that in each round, the number of calls is a power of 4. 1st round: 4 calls = 4 = 41 2nd round: 16 calls = 4 4 = 42 So during the 4th round, there will be 44 calls. 44 = 4 4 4 4 = 256 During the 4th round of calls, 256 families will be notified. Drawing a diagram helps you see how to use exponents to solve the problem.
1 Understand the Problem Check It Out: Example 3 A phone tree is used to contact families at Paul’s school. The secretary calls 3 families. Then each family calls 3 other families, and so on. How many families will be notified during the fourth round of calls? The answer will be the number of families called in the 4th round. List the important information: • The secretary calls 3 families. • Each family calls 3 families.
2 Make a Plan You can draw a diagram to see how many calls are in each round. Secretary 1st round–3 calls 2nd round–9 calls
3 Solve 4 Look Back Notice that in each round, the number of calls is a power of 3. 1st round: 3 calls = 3 = 31 2nd round: 9 calls = 3 3 = 32 So during the 4th round, there will be 34 calls. 34 = 3 3 3 3 = 81 During the 4th round of calls, 81 families will be notified. Drawing a diagram helps you see how to use exponents to solve the problem.