3.1+Subtracting+on+a+Chip+Board

HAH 7B April.24.2009

A.) Use a chip board and black and red chips to find each sum or difference.** 1. -8 - -7 = -1 2. +8 + -7 = 1 3. -6 - -2 = -4 4. +6 + -2 = 4
 * __Problem 3.1__

Find three ways to represent -8 on a chipboard** O = +1 O = -1 1. OOOO 2. OOOO 3. OOOO OOOO OOOO OOOO OOOO O
 * B.) In Problem 2.2, you simplified chip boards to find the number represented. For example, each chip board below represents +3.

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.**
 * 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 repersent subtracting -10.

She needs to remove all the 8 chips and add two black ones to show the positive.


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

Drew can’t move 7 red chips off but he can add 2 black chips to represent the answer.


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

1. 10 - 12 = -2 I used ten red chips but since I couldn’t take away 12 chips I added 2 black chips. 2. 7 - -2 = 5 I used seven red chips took away two and the difference was five. 3. -5 - 6 = 1 I had five black chips I took six away and I got one red chip. 4. -3 - -7 = -10 I had three black chips I added seven more and I got ten black chips.

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.** O = -1 O = +1 1. OOO -5 - 0 = 2. OOO -6 - 1= 3. OOOO -7 - -2 = OO OOO O OOOO O 2.) a. 7 b.18 c.42 d.0 3.) a.12 b.3 c.31 d.100
 * Problem 3.1 Follow Up