3.1+Subtracting+on+a+Chip+Board

A.R.** Notes: Black Chips= +1 Red chips= -1 Yellow chips= extra
 * April 8, 2009
 * Big Idea: Negative numbers help us model many real world situations**
 * Essential Q: How do I find the difference between integers?

A. Use a chip board and black and red chips to find the sum of each difference.

1. -8 - -7 = -1 2. +8 + -7 = 1 3. -6 - -2= -4 4. +6 + -2= 4

B. In Problem 2.2, you simplified chip boards to find the number represented. For example, each chip board below represents +3. Find three ways to represent -8 on a chip board.**


 * C. Jing-Mei wants to find -8 - -10 by using a chip board. She puts eight red chips on the board to represent -8 but then gets stuck because she cannot remove ten red chips to represent subtracting -10. How can Jing-Mei show -8 on a chip board so that she can remove ten red chips? What is -8 - -10? Explain how you determined your answer.** The answer is 2.
 * [[image:carchip.gif]]

D. Drew wants to find +5 - +7 by using a chip board. How can he show +5 on a chip board so he can take away seven black chips to represent subtracting +7. What is +5 - +7? Explain how you determined your answer.** The answer is -2.


 * [[image:darchip.gif]]

E. Use a chip board and black and red chips to find each difference. For each difference, tell how many chips of eachcolor you used to represent the first integer so that you couldtake away chips to represent subtracting the second integer.

1. 10 - 12=** -2
 * 2. 7 - -2=** 9
 * 3. -5 - -6=** -11
 * 4. -3 - -7=** -10




 * Problem 3.1 Follow Up

1. Find three ways to show -5 on the chip board. For each representation, write a subtraction problem that would be easy to solve if you started with that representation.



2. Find each absolute value.** a. -7 = 7 b. 18 = 18 c. -42 = 42 d.-0 = 0

a.12 = -12, 12 b.3 = 3,-3 c.31 = 31, -31 d.100 = -100, 100
 * 3. Tell which numbers have the given number as their absolute value.**