1. Course 2, Chapter 3 PSI Subtract. 1. 4 + (−5) 2. −14 − 34 3. −45 − (−8) Evaluate each expression if a = −2, b = 3, and c = −1 4. c − b 5. 9 − a 6. What is −4 subtracted from −3?

2. Course 2, Chapter 3 PSI ANSWERS 1. −1 2. −48 3. −37 4. −4 5. 11 6. C

3. WHAT happens when you add, subtract, multiply, and divide integers? Course 2, Chapter 3 PSI The Number System

4. The Look For a Pattern problem- solving strategy to find patterns in mathematical situations Course 2, Chapter 3 PSI The Number System

5. Course 2, Chapter 3 PSI The Number System

6. Course 2, Chapter 3 PSI

9. Case #3 Nature A sunflower usually has two different spirals of seeds, one with 34 seeds and the other with 55 seeds. The numbers 34 and 55 are part of the Fibonacci sequence. 1, 1, 2, 3, 5, 8, 13, 21, 34, 55,... Find the pattern in the Fibonacci sequence and identify the next two terms. Read the problem. What are you being asked to find? What is your strategy to solve this problem? Use your strategy to solve the problem. Does your answer make sense? Use information from the problem to check your answer. The Number System

10. Course 2, Chapter 3 PSI The Number System

11. Course 2, Chapter 3 PSI Case #5 Geometry The pattern at the right is made from toothpicks. How many toothpicks would be needed for the sixth term in the pattern? Read the problem. What are you being asked to find? What is your strategy to solve this problem? Use your strategy to solve the problem. Does your answer make sense? Use information from the problem to check your answer. The Number System

12. Course 2, Chapter 3 PSI Case #6 Diving A diver descends to –15 feet after 1 minute, –30 feet after 2 minutes, and –45 feet after 3 minutes. If she keeps descending at this rate, find the diver’s position after ten minutes. Read the problem. What are you being asked to find? What is your strategy to solve this problem? Use your problem-solving strategy to solve the problem. Does your answer make sense? Use information from the problem to check your answer. The Number System