1. Warm up 1. 2 2 2 = 2. 3 3 3 3 = 3. 5 5 5 = 4. 4 4 4 = 5. You have just installed a water pond in your backyard. You intend to place water lilies in the pond. According to the package a water lily doubles in size every day. From the time you install the first lily until the entire surface of the pond is covered will take 20 days. How long will it take the pond to be half covered?

2. Exponents  7 th Grade Mathematics  Today we will represent numbers by using exponents

3. Vocabulary Look up the following terms and write their definitions in your notebook. 1. power 2. exponent 3. base

4. Evaluating powers  Find each value. A. 5 2 F. 11 2 B. 2 6 G. 8 3 C. 4 4 H. 5 1 D. 7 3 I. 2 3 E. 3 4 J. 3 0

5. Recall  Any number to the first power is equal to that number.  Example: 6 1 = 613 1 = 13 25 1 = 25  Any number to the zero power, except zero, is equal to 1.  Example: 6 0 = 1 10 0 = 1 19 0 = 1

6. Find each value. 1. 2 2 + 2 5 2. 3 4 + 3 3 3. 6 2 + 6 0 4. 3 3 + 4 2 - 5 1

7. Real-World Example  On Monday, Erik tells 3 people a secret. The next day each of them tells 3 more people. If this pattern continues, how many people besides Erik will know the secret?

8. Write  Describe the relationship between 3 5 and 3 6.  Answer: The value of 36 is 3 times the value of 3 5. 3 6 = 729 and 3 5 = 243.

9. Write  Is 2 5 greater than or less than 3 3 ? Explain your answer.

10. Write (Journal)  Think about how exponents can be used to write large numbers more efficiently. Write an explanation about why this is useful and give examples to show the efficiency of this method.

11. Homework  Textbook p. 62 (10-21; 36-44)